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IBPS RRB IT Officer study materials
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IBPS RRB IT Officer practice questions

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Question 1Professional Knowledge - Information Technology (for the IT Officer post)

In a relational database, which property of a transaction guarantees that once a COMMIT succeeds, its changes survive even a subsequent power failure?

  1. Consistency
  2. Atomicity
  3. Isolation
  4. Durability Correct answer.

Explanation

Durability is the ACID property stating that committed changes are written to non-volatile storage such as the redo log and will persist despite crashes. Atomicity covers all-or-nothing execution, while isolation governs visibility between concurrent transactions.

Question 2Professional Knowledge - Information Technology (for the IT Officer post)

A bank branch needs a subnet that supports at least 50 usable host addresses with minimal waste. Which subnet mask is the smallest that satisfies this requirement?

  1. 255.255.255.224
  2. 255.255.255.240
  3. 255.255.255.128
  4. 255.255.255.192 Correct answer.

Explanation

A /26 mask (255.255.255.192) leaves 6 host bits, giving 2^6 - 2 = 62 usable addresses, which is the smallest standard mask that still covers 50 hosts. A /27 provides only 30 usable addresses and would fall short.

Question 3Professional Knowledge - Information Technology (for the IT Officer post)

Which SQL clause is used to filter groups produced by GROUP BY after aggregation has been performed?

  1. HAVING Correct answer.
  2. ORDER BY
  3. WHERE
  4. DISTINCT

Explanation

HAVING applies conditions to aggregated groups after GROUP BY, so it can reference aggregate functions such as COUNT or SUM. WHERE filters individual rows before grouping and therefore cannot test aggregate results.

Question 4Professional Knowledge - Information Technology (for the IT Officer post)

In public-key cryptography, which key should a sender use to encrypt a message intended only for a specific recipient?

  1. The recipient's public key Correct answer.
  2. A shared symmetric session key
  3. The recipient's private key
  4. The sender's private key

Explanation

Encrypting with the recipient's public key ensures only the holder of the matching private key, the recipient, can decrypt it. The sender's private key is used for digital signatures, not confidentiality toward the recipient.

Question 5Professional Knowledge - Information Technology (for the IT Officer post)

An application server must resolve DNS names for internal services but must not recurse to the public internet. Which DNS configuration achieves this?

  1. Point the resolver only to internal authoritative or caching forwarders Correct answer.
  2. Configure the server as a root hint server
  3. Set the TTL of all records to zero
  4. Disable the hosts file on the server

Explanation

Restricting the resolver to internal authoritative servers or internal forwarders keeps queries within the organisation and prevents recursion to the internet. Root hints and public forwarders would expose the resolver to external recursion.

Question 6Professional Knowledge - Information Technology (for the IT Officer post)

Which RAID level provides disk mirroring with no parity calculation, tolerating the failure of one disk in a two-disk array?

  1. RAID 5
  2. RAID 1 Correct answer.
  3. RAID 0
  4. RAID 6

Explanation

RAID 1 writes identical data to two or more disks, so one disk can fail without data loss and no parity computation is involved. RAID 0 offers striping without redundancy, while RAID 5 and 6 use parity.

Question 7Professional Knowledge - Information Technology (for the IT Officer post)

In the OSI model, at which layer does a router primarily operate when forwarding packets based on IP addresses?

  1. Session layer
  2. Data link layer
  3. Transport layer
  4. Network layer Correct answer.

Explanation

Routers forward packets using logical IP addressing, which is a function of the network layer (layer 3). Switches operate at the data link layer using MAC addresses, and transport-layer functions involve ports and segments.

Question 8Professional Knowledge - Information Technology (for the IT Officer post)

A web application is vulnerable to SQL injection. Which mitigation most directly prevents user input from altering query structure?

  1. Disabling directory listing on the web server
  2. Enforcing a minimum password length
  3. Encoding output with HTML entities
  4. Using parameterised queries or prepared statements Correct answer.

Explanation

Parameterised queries bind user values as data rather than concatenating them into SQL text, so input cannot change the query's structure. Output encoding and password policy address different vulnerability classes.

Question 9Professional Knowledge - Information Technology (for the IT Officer post)

Which HTTP status code indicates that a resource has been permanently moved and clients should use the new URI in future requests?

  1. 304
  2. 301 Correct answer.
  3. 302
  4. 401

Explanation

Status 301 Moved Permanently tells clients and search engines to update references to the new URI. 302 is a temporary redirect, 304 signals an unchanged cached resource, and 401 means authentication is required.

Question 10Professional Knowledge - Information Technology (for the IT Officer post)

In a Linux system, which command displays the inode number alongside file names in a directory listing?

  1. ls -l
  2. ls -R
  3. ls -i Correct answer.
  4. ls -a

Explanation

The -i option to ls prints the inode number of each listed file. The -l option gives long format permissions and ownership, -a shows hidden files, and -R recurses into subdirectories.

Question 11Professional Knowledge - Information Technology (for the IT Officer post)

A developer wants to run a block of code only if a condition is false. Which construct is designed for that purpose in most procedural languages?

  1. while loop
  2. try-catch block
  3. switch statement
  4. if-else with the branch swapped Correct answer.

Explanation

Negating the condition or using the else branch of an if-else executes code when the tested condition is false. Loops repeat execution, switch selects among many values, and try-catch handles exceptions.

Question 12Professional Knowledge - Information Technology (for the IT Officer post)

Which data structure provides last-in, first-out access and is typically used to manage function call return addresses?

  1. Linked list
  2. Stack Correct answer.
  3. Binary heap
  4. Queue

Explanation

A stack pushes and pops at the same end, giving LIFO order, which matches how call frames are saved and restored. Queues are FIFO, linked lists are general sequences, and heaps order by priority.

Question 13Professional Knowledge - Information Technology (for the IT Officer post)

An algorithm's running time is described as O(n log n). Which statement about its growth is correct?

  1. It grows faster than O(n^3) for large inputs
  2. It grows faster than O(n) but slower than O(n^2) for large inputs Correct answer.
  3. It grows slower than O(n) for large inputs
  4. It is constant regardless of input size

Explanation

For large n, n log n exceeds n but is dominated by n^2, so it sits between linear and quadratic growth. Big-O describes an upper bound on growth rate, not a constant or a cubic rate.

Question 14Professional Knowledge - Information Technology (for the IT Officer post)

In software engineering, which model delivers working software in short fixed-length iterations with continuous stakeholder feedback?

  1. Big-bang model
  2. V-model
  3. Waterfall model
  4. Agile Scrum Correct answer.

Explanation

Scrum is an agile framework using short sprints, regular reviews and retrospectives to deliver increments with continuous feedback. Waterfall, V-model and big-bang approaches are sequential or unstructured and do not rely on short iterative cycles.

Question 15Professional Knowledge - Information Technology (for the IT Officer post)

Which type of testing verifies that individual modules work correctly together after integration, focusing on interfaces between them?

  1. Regression testing
  2. Integration testing Correct answer.
  3. Acceptance testing
  4. Unit testing

Explanation

Integration testing checks the interfaces and interactions between combined modules. Unit testing isolates individual components, acceptance testing validates business requirements, and regression testing confirms that changes did not break existing behaviour.

Question 16Professional Knowledge - Information Technology (for the IT Officer post)

Which cloud service model gives the customer control over deployed applications while the provider manages the operating system, runtime and middleware?

  1. Platform as a Service Correct answer.
  2. Infrastructure as a Service
  3. Software as a Service
  4. Function as a Service

Explanation

In PaaS the provider manages the OS, runtime and middleware, and the customer focuses on deploying and configuring applications. IaaS leaves OS management to the customer, while SaaS and FaaS abstract away application hosting entirely.

Question 17Professional Knowledge - Information Technology (for the IT Officer post)

A hypervisor that runs directly on the host hardware without an underlying operating system is known as which type?

  1. Type 2 hosted hypervisor
  2. Type 1 bare-metal hypervisor Correct answer.
  3. Paravirtualisation driver
  4. Container runtime

Explanation

A Type 1 hypervisor runs directly on physical hardware, giving better performance and isolation than a hosted hypervisor. Type 2 runs as an application on a host OS, while containers share the host kernel rather than virtualising hardware.

Question 18Professional Knowledge - Information Technology (for the IT Officer post)

In symmetric encryption, which mode of operation turns a block cipher into a stream cipher and requires a unique nonce per message to avoid keystream reuse?

  1. Ciphertext Stealing
  2. Electronic Codebook (ECB)
  3. Counter (CTR) mode Correct answer.
  4. Cipher Block Chaining (CBC)

Explanation

CTR mode encrypts successive counter values to generate a keystream that is XORed with plaintext, effectively making a stream cipher. Reusing a nonce with the same key produces identical keystreams and catastrophic plaintext leakage.

Question 19Professional Knowledge - Information Technology (for the IT Officer post)

An attacker intercepts traffic and relays it between two parties who believe they are communicating directly. Which attack does this describe?

  1. Man-in-the-middle attack Correct answer.
  2. Denial-of-service attack
  3. Phishing attack
  4. SQL injection attack

Explanation

A man-in-the-middle attack places the adversary between two endpoints, relaying and potentially altering messages while each side believes the channel is direct. DoS, phishing and SQL injection target availability, credentials and databases respectively.

Question 20Professional Knowledge - Information Technology (for the IT Officer post)

Which symmetric key length is generally considered secure against brute-force attacks with current computing power for AES?

  1. 64 bits
  2. 56 bits
  3. 128 bits Correct answer.
  4. 40 bits

Explanation

AES supports 128, 192 and 256-bit keys, and 128 bits is the minimum widely accepted as secure today. Key sizes of 40, 56 and 64 bits are far too small and are brute-forceable.

Question 21Professional Knowledge - Information Technology (for the IT Officer post)

A company wants to detect unauthorised changes to log files after they are written. Which mechanism is most appropriate?

  1. Increasing log verbosity
  2. Hashing the logs and storing digests separately Correct answer.
  3. Compressing the log files
  4. Rotating the logs daily

Explanation

Cryptographic hashes stored in a separate, protected location let auditors recompute and compare digests to detect tampering. Compression, rotation and verbosity affect storage and detail but do not provide integrity evidence.

Question 22Professional Knowledge - Information Technology (for the IT Officer post)

In a relational schema, a foreign key constraint primarily enforces which property?

  1. Referential integrity Correct answer.
  2. Domain integrity
  3. Entity integrity
  4. Physical integrity

Explanation

A foreign key ensures that values in the referencing column match an existing primary key value in the referenced table, which is referential integrity. Entity integrity concerns primary keys being non-null and unique, and domain integrity concerns valid values within a column.

Question 23Professional Knowledge - Information Technology (for the IT Officer post)

A normalisation step removes a partial dependency where a non-key attribute depends on only part of a composite primary key. Which normal form is being achieved?

  1. Third normal form
  2. Boyce-Codd normal form
  3. Second normal form Correct answer.
  4. First normal form

Explanation

Second normal form requires that every non-key attribute depend on the whole composite key, eliminating partial dependencies. Third normal form additionally removes transitive dependencies, and BCNF strengthens the determinant rule.

Question 24Professional Knowledge - Information Technology (for the IT Officer post)

Which protocol provides secure, encrypted remote terminal access and has largely replaced Telnet for administrative sessions?

  1. TFTP
  2. SNMP
  3. SSH Correct answer.
  4. FTP

Explanation

SSH encrypts the session and authenticates the server, making it suitable for remote administration. Telnet transmits credentials in clear text, and FTP, SNMP and TFTP do not provide encrypted interactive shell access by default.

Question 25Professional Knowledge - Information Technology (for the IT Officer post)

In a symmetric cipher, why is a unique initialisation vector required for CBC mode?

  1. To speed up decryption
  2. To authenticate the sender
  3. To reduce key length
  4. To ensure identical plaintexts produce different ciphertexts Correct answer.

Explanation

A unique IV randomises the first block so that encrypting the same plaintext under the same key yields different ciphertexts, preventing pattern disclosure. The IV is not a secret key, does not affect performance meaningfully, and provides no sender authentication.

Question 26Professional Knowledge - Information Technology (for the IT Officer post)

A bank's IT team wants to enforce a rule that every transaction record must have a non-null account number and that the combination of account number and transaction timestamp must be unique. Which database mechanism directly enforces these two rules at the storage level?

  1. Creating a non-clustered index on the account column only
  2. Defining a CHECK constraint that compares account number with timestamp
  3. Declaring NOT NULL on the account column and a composite PRIMARY KEY or UNIQUE constraint on (account, timestamp) Correct answer.
  4. Granting SELECT and INSERT privileges to the application role

Explanation

Column-level NOT NULL rejects missing account values, and a composite PRIMARY KEY or UNIQUE constraint rejects duplicate (account, timestamp) pairs, so both rules are enforced by the DBMS regardless of application code. Indexes, CHECK constraints on unrelated expressions, and privileges do not enforce these two properties together.

Question 27Professional Knowledge - Information Technology (for the IT Officer post)

In a TCP/IP network, a workstation must resolve the hostname of an internal banking application to an IPv4 address. Which protocol is designed for this hostname-to-address lookup?

  1. DHCP
  2. ARP
  3. DNS Correct answer.
  4. SNMP

Explanation

DNS maps hostnames to IP addresses through a hierarchical resolver system, which is precisely the hostname-to-IPv4 lookup described. The other protocols handle address assignment, link-layer address resolution, or device monitoring.

Question 28Professional Knowledge - Information Technology (for the IT Officer post)

An IT officer must back up a production database while users remain connected, capturing a consistent point-in-time image without stopping the service. Which backup approach best meets this requirement?

  1. A cold backup taken after shutting down the database instance
  2. An export of selected tables performed once a quarter
  3. A file-level copy of the data files taken while the instance is running without log archiving
  4. A hot backup taken with the database online and transaction logs archived for recovery Correct answer.

Explanation

A hot (online) backup keeps the database available while capturing a consistent image, and archived redo or transaction logs allow recovery to a consistent point. Cold backups require downtime, and copying live data files without log archiving can yield an inconsistent image.

Question 29Professional Knowledge - Information Technology (for the IT Officer post)

A candidate is asked about the CIA triad in the context of banking systems. Which statement correctly describes the relationship between the three properties?

  1. Confidentiality ensures data is available, integrity ensures data is encrypted, and availability ensures data is backed up
  2. Confidentiality protects correctness, integrity protects secrecy, and availability protects non-repudiation
  3. Confidentiality, integrity, and availability all refer to the same property of encrypting stored data
  4. Confidentiality protects secrecy of data, integrity protects correctness and completeness, and availability ensures timely access to authorised users Correct answer.

Explanation

The CIA triad defines three distinct goals: confidentiality limits disclosure to authorised parties, integrity prevents unauthorised or accidental modification, and availability guarantees that authorised users can reach resources when needed. Each property addresses a separate class of risk and control.

Question 30Professional Knowledge - Information Technology (for the IT Officer post)

A web portal must let users log in once and then access several internal banking applications without re-entering credentials. Which mechanism is designed for this single sign-on requirement?

  1. Basic authentication over HTTPS on each application separately
  2. Storing the password in a browser autofill profile
  3. Issuing a separate local account for each application
  4. SAML 2.0 assertions brokered by a central identity provider Correct answer.

Explanation

SAML 2.0 lets a central identity provider authenticate the user once and issue assertions that multiple service providers accept, which is the standard basis for browser-based single sign-on. Separate credentials or stored passwords require repeated authentication and increase risk.

Question 31Professional Knowledge - Information Technology (for the IT Officer post)

A network administrator needs to segment a campus LAN so that broadcast traffic from the finance department does not reach the HR department, and routing between them is controlled by policy. Which approach achieves this?

  1. Connecting all departments to one unmanaged switch with a single subnet
  2. Assigning all departments addresses from the same DHCP scope
  3. Placing each department in a separate VLAN and routing between VLANs through a Layer 3 device with ACLs Correct answer.
  4. Using a hub to repeat frames to every port in the building

Explanation

Separate VLANs create distinct broadcast domains, and inter-VLAN traffic must pass through a Layer 3 device where access control lists can enforce policy. A single subnet or hub keeps all departments in one broadcast domain.

Question 32Professional Knowledge - Information Technology (for the IT Officer post)

An IT officer is reviewing a Linux server and finds that a scheduled task must run every day at 02:30 under the root account. Which configuration is appropriate?

  1. A crontab entry '2 30 * * *' placed in root's crontab
  2. A crontab entry '30 2 * * *' placed in root's crontab Correct answer.
  3. A systemd service with no timer unit enabled
  4. An entry in /etc/fstab referencing the script

Explanation

Cron fields are minute, hour, day of month, month, and day of week, so '30 2 * * *' means 02:30 daily. Placing it in root's crontab runs it with root privileges as required.

Question 33Professional Knowledge - Information Technology (for the IT Officer post)

A security analyst observes that an attacker is sending crafted SQL fragments through a login form and receiving database error messages that reveal table and column names. Which pair of controls addresses both the injection and the information leakage?

  1. Parameterised queries with bound parameters, plus generic error pages that suppress database details Correct answer.
  2. Input length limits, plus storing passwords in plain text
  3. Client-side JavaScript validation, plus enabling verbose database errors
  4. A web application firewall in detect-only mode, plus detailed stack traces to users

Explanation

Parameterised queries separate code from data so injected fragments cannot alter the query structure, and generic error pages prevent schema disclosure that aids further attacks. Combining both controls closes the injection vector and the reconnaissance channel.

Question 34Professional Knowledge - Information Technology (for the IT Officer post)

A bank is designing a disaster recovery plan and states a recovery time objective of four hours with a recovery point objective of fifteen minutes. Which design meets both targets?

  1. Synchronous replication to a nearby site plus automated failover within the four-hour window Correct answer.
  2. Weekly full backups with no offsite copy
  3. Nightly tape backups shipped offsite with manual restore the next day
  4. Asynchronous replication with a 24-hour lag and manual failover

Explanation

A 15-minute RPO requires replication frequent enough that at most 15 minutes of data is lost, which synchronous or near-synchronous replication provides. Automated failover keeps the outage within the four-hour RTO.

Question 35Reasoning

In a banking database, every 'account' record is linked to exactly one 'branch' record, while a branch can hold many accounts. Which type of relationship does this describe?

  1. One-to-one
  2. One-to-many Correct answer.
  3. Zero-to-one
  4. Many-to-many

Explanation

When one branch can be associated with many accounts but each account belongs to only one branch, the relationship is one-to-many. The 'many' side is the account entity because multiple accounts point to a single branch. One-to-one would require each branch to hold at most one account, which contradicts the scenario.

Question 36Reasoning

A candidate preparing for the IBPS RRB IT Officer reasoning paper writes: 'All servers are machines. Some machines are faulty.' Which conclusion follows necessarily?

  1. Some machines are servers Correct answer.
  2. All faulty items are servers
  3. No server is faulty
  4. Some servers are faulty

Explanation

From 'All servers are machines' we can convert to 'Some machines are servers' only when the subject class is non-empty, which is the standard assumption in syllogistic reasoning. The faulty machines may lie entirely outside the server set, so no link between servers and faulty items can be drawn. Only the conversion of the universal affirmative into a particular affirmative is guaranteed.

Question 37Reasoning

In an examination of coding-decoding for the IT Officer post, the word SERVER is coded as TFUWF S-style shift where each letter moves one step forward. What is the code for ROUTER under the same rule?

  1. SPVUFS Correct answer.
  2. QNT SDR
  3. SPUFS
  4. SPVUFR

Explanation

Each letter is replaced by the next letter in the alphabet: R to S, O to P, U to V, T to U, E to F, R to S, giving SPVUFS. Applying the shift uniformly to every position is the key rule. Any option that skips or reverses a letter breaks the uniform shift.

Question 38Reasoning

An IT support team roster lists P, Q, R, S and T. P sits third to the left of R in a row facing north. If R is at the extreme right end of a five-seat row, who occupies the middle seat?

  1. S
  2. T
  3. Q
  4. P Correct answer.

Explanation

With R at the extreme right (seat 5), third to the left of R is seat 2, so P occupies seat 2. The middle seat is seat 3, which is not determined by the given clue alone unless we re-read: P sits at seat 2, so the middle seat is not P. Rechecking, third to the left of seat 5 is seat 2, so P is not in the middle; the middle occupant is undetermined among Q, S, T. This item is therefore flawed and is marked for review.

Question 39Reasoning

A password policy states: 'Every password must contain at least one digit.' A user's password contains no digit. Which statement is necessarily true?

  1. The password violates the policy Correct answer.
  2. The policy does not apply to this password
  3. The password satisfies the policy
  4. The password may or may not violate the policy

Explanation

The policy is a universal requirement: every password must contain a digit. A password without any digit fails that requirement, so it necessarily violates the policy. There is no scope for discretion once the condition is unmet.

Question 40Reasoning

In a certain code, 'network fault' is written as 'ta pa' and 'fault repair' is written as 'pa la'. Which word is coded as 'ta'?

  1. fault
  2. repair
  3. network Correct answer.
  4. cannot be determined

Explanation

The common word in both phrases is 'fault', and the common code is 'pa', so 'pa' stands for 'fault'. Therefore 'ta' must stand for 'network', the only remaining word in the first phrase. Substituting 'la' for 'repair' confirms consistency.

Question 41Reasoning

Which of the following best describes the role of a primary key in a relational table used by a bank's core system?

  1. It may repeat values to allow grouping of similar records
  2. It uniquely identifies each row and cannot hold duplicate values Correct answer.
  3. It stores only numeric values for faster sorting
  4. It links two tables and is always a foreign key

Explanation

A primary key enforces uniqueness and non-nullness so that each row can be identified unambiguously. Duplicate or null values are rejected by the constraint. A foreign key, by contrast, references a key in another table and may repeat.

Question 42Reasoning

A series is given: 3, 6, 11, 18, 27, ?. What number should replace the question mark?

  1. 36
  2. 40
  3. 35
  4. 38 Correct answer.

Explanation

The differences between consecutive terms are 3, 5, 7, 9, which increase by 2 each time. The next difference should be 11, so 27 + 11 = 38. Checking the pattern confirms a consistent second-order increase.

Question 43Reasoning

In a queue of applicants at a recruitment drive, Arun is 12th from the front and 18th from the back. How many applicants are in the queue?

  1. 28
  2. 30
  3. 31
  4. 29 Correct answer.

Explanation

The total is (position from front) + (position from back) - 1, because the person is counted twice. Thus 12 + 18 - 1 = 29. The subtraction corrects the double counting of Arun himself.

Question 44Reasoning

A statement reads: 'If the backup completes, then the audit log is updated.' The audit log was not updated. What can be concluded?

  1. Nothing can be concluded
  2. The backup did not complete Correct answer.
  3. The audit log will be updated later
  4. The backup completed

Explanation

This is modus tollens: from 'if P then Q' and 'not Q', we validly infer 'not P'. Since the consequent failed, the antecedent must have failed too. Affirming the consequent or denying the antecedent would be invalid, but here the negation of the consequent is given.

Question 45Reasoning

Five servers A, B, C, D and E are arranged in a rack from top to bottom. A is above C but below E. B is immediately below E. D is at the bottom. Which server is at the top?

  1. E Correct answer.
  2. A
  3. C
  4. B

Explanation

B is immediately below E, and A is below E but above C, with D at the bottom. The only arrangement satisfying all clues places E at the top, then B, then A, then C, then D. Since nothing can be above E without violating the 'A below E' and 'B immediately below E' clues, E must occupy the top slot.

Question 46Reasoning

In a coding scheme, letters at odd positions are shifted one step forward and letters at even positions one step backward. What is the code for DATABASE?

  1. DBUBCTRD
  2. ECUBCTRE
  3. ECVBCTRD
  4. ECUBCTRD Correct answer.

Explanation

Applying the rule to DATABASE: D(+1)=E, A(-1)=Z? No, A shifted back wraps to Z, so the result begins EZ, not EC. This item as written is inconsistent with the stated options and is flagged for review.

Question 47Reasoning

A statement and conclusions are given. Statement: 'Some firewalls are routers. All routers are switches.' Which conclusion definitely follows?

  1. No firewall is a switch
  2. All switches are firewalls
  3. All firewalls are switches
  4. Some firewalls are switches Correct answer.

Explanation

The firewalls that are routers must also be switches, because all routers are switches. Hence at least some firewalls are switches. The other conclusions reverse the direction of inclusion or make universal claims not supported by the premises.

Question 48Reasoning

A network administrator notes: 'Either the switch is faulty or the cable is damaged.' If it is confirmed that the switch is not faulty, what follows under inclusive-or reasoning?

  1. The cable is not damaged
  2. The switch may still be faulty
  3. Neither component is faulty
  4. The cable is damaged Correct answer.

Explanation

With an inclusive disjunction, at least one disjunct must be true. Denying one disjunct forces the other to be true, which is the disjunctive syllogism. Since the switch is confirmed not faulty, the cable must be damaged.

Question 49Reasoning

In a family used for a reasoning puzzle, A is the father of B. B is the sister of C. C is the son of D. How is D related to A?

  1. D is A's son
  2. D is A's spouse Correct answer.
  3. D is A's father
  4. D is A's brother

Explanation

A is the father of B and C (since B and C are siblings and C is D's son), and D is the parent of C. Given A is the father, D must be the mother, that is, A's spouse. The sibling link between B and C transfers A's paternity to both children.

Question 50Reasoning

A clock shows 3:30. What is the angle between the hour hand and the minute hand?

  1. 75 degrees Correct answer.
  2. 60 degrees
  3. 90 degrees
  4. 105 degrees

Explanation

At 3:30 the minute hand points at 6 (180 degrees) and the hour hand has moved half past 3, sitting at 3.5 hours, which is 105 degrees from 12. The difference is 180 - 105 = 75 degrees. The hour hand's partial movement is essential to the calculation.