CSA Civil Service Exam cheat sheet

Analogies follow a fixed relation type: synonym, antonym, part-to-whole, cause-to-effect, worker-to-tool, or category-to-member; name the relation in a phrase before checking options.

In odd-one-out items, test each option against a shared class; the outlier is the only one that fails a property all others satisfy, not merely the least familiar word.

Word-pair direction matters: if A is a tool used by B, then B is the user of A; reversed order eliminates an option even when the words match.

For letter-series items, convert letters to positions 1-26 (A=1, Z=26) and compute gaps; gaps often follow +2, +3, +4 or alternate two interleaved sequences.

In syllogism items, treat 'all', 'no', and 'some' formally: 'some' premises never yield a universal conclusion, and two negative premises yield no valid conclusion.

For statement-assumption items, the assumption must be necessary for the statement to hold; options that merely support or repeat the statement are not assumptions.

Cause-and-effect items: if both events could stem from a third factor, mark them as independent rather than cause and effect.

In word-usage items, a word is correct only if its meaning in the sentence matches its standard dictionary sense and its part of speech fits the slot.

Percentage change = (new − old) / old × 100; successive changes of a% and b% combine as a + b + ab/100, not a + b.

Compound interest: A = P(1 + r/n)^(nt); for annual compounding, A = P(1 + r)^t. Simple interest: SI = PRT/100.

Profit and loss percentages are taken on cost price unless stated otherwise; selling price = CP × (100 + profit%)/100.

Ratio scaling: if a:b = m:n, write a = mk and b = nk, then substitute into the given sum or difference to solve for k.

Average speed for equal distances = 2xy/(x + y); for equal times it is the simple mean (x + y)/2.

Work problems: if A finishes in a days and B in b days, together they take ab/(a + b) days; rates add, times do not.

Divisibility: by 3 or 9 when digit sum is divisible; by 4 when the last two digits are; by 8 when the last three digits are; by 11 when alternating digit sums differ by a multiple of 11.

HCF × LCM of two numbers = product of the two numbers; use this to find one value when the other three are known.

Contrapositive is valid: from 'if P then Q' infer 'if not Q then not P'. The converse ('if Q then P') and inverse ('if not P then not Q') are not valid.

In seating arrangements, draw positions before reading clues; fix the most constrained person first, then place others relative to that anchor.

For blood-relation puzzles, build a family tree with symbols for gender and generation; never infer gender from a role word alone unless the clue states it.

Direction sense: track net displacement with signed axes; facing changes rotate the axis, so 'left' after facing south means east.

In ranking puzzles, total = (rank from top) + (rank from bottom) − 1; use this to find class size or a missing rank.

For coding-decoding, compare plaintext and cipher letters position by position to identify a shift, reversal, or substitution pattern before applying it.

In input-output or arrangement machines, identify the single rule that transforms each step; the rule must explain every line, not just the first.

For 'either-or' conclusions in syllogisms, the pair must be complementary (one positive, one negative) with the same subject and predicate.

Grouping puzzles: count slots and entities first; if slots exceed entities, one entity repeats or one slot stays empty - state which before solving.

Conditional rules of the form 'if X is in, Y is out' are equivalent to 'X and Y cannot both be in'; use this to eliminate pairs quickly.

A rule 'A is immediately before B' fixes the block AB; treat the block as a single unit when counting arrangements.

When a question adds a condition, apply it only to that question; do not carry it into other items in the set.

For scheduling with days or slots, list all slots and fill fixed ones first; open slots then determine what is possible.

Number of linear arrangements of n distinct items = n!; if k specific items must stay together, treat them as one unit giving (n − k + 1)! × k!.

In selection puzzles, 'at least one of A and B' means the pair cannot both be excluded; test options that exclude both first.

If a question asks what 'must be true', eliminate any option that admits a single valid counter-arrangement.

Read the axis units and the year labels before computing; a chart in thousands versus lakhs changes every answer by a factor of 100.

Percentage of total = (part / total) × 100; percentage increase = (later − earlier) / earlier × 100 - the denominator is always the base period.

In pie charts, each sector's angle = (value / total) × 360°; a sector of 72° represents 20% of the total.

For tables with mixed units, convert everything to one unit before comparing rows or computing ratios.

Average = sum of values / count; for grouped data, use the class midpoint times frequency, then divide by total frequency.

Ratio between two bars = height of first / height of second; keep the ratio in lowest terms only after confirming both use the same scale.

In line graphs, a steeper slope means a larger absolute change per unit period, not necessarily a larger percentage change.

When a question says 'approximately', round inputs to two significant figures before dividing to avoid wasted computation.

The Constitution of India came into force on 26 January 1950; the Constituent Assembly adopted it on 26 November 1949.

Fundamental Rights are in Part III (Articles 12-35); Directive Principles are in Part IV (Articles 36-51) and are not enforceable in court.

The President is the constitutional head of state; executive power is exercised on the advice of the Council of Ministers under Article 74.

The Election Commission of India is a constitutional body under Article 324; the Comptroller and Auditor General is under Article 148.

The Reserve Bank of India was established in 1935 and nationalised in 1949; it sets the repo rate through the Monetary Policy Committee.

The United Nations was founded in 1945; its principal organs include the General Assembly, Security Council, and International Court of Justice at The Hague.

India's Five-Year Plans were formulated by the Planning Commission (1950); NITI Aayog replaced it in 2015.

For current affairs items, verify the date and officeholder from the question's own timeframe; answers change with each appointment or election.

Subject-verb agreement: a singular subject takes a singular verb; phrases between them ('along with', 'as well as') do not change the number.

'Neither...nor' and 'either...or' take a verb agreeing with the nearer subject.

Use 'fewer' with countable nouns and 'less' with uncountable nouns; 'amount' pairs with uncountable, 'number' with countable.

Present perfect ('has done') links a past action to the present; simple past ('did') is used with a definite finished time such as 'yesterday'.

Passive voice: object becomes subject and the verb becomes be + past participle; only transitive verbs can be made passive.

In reading comprehension, the answer must be supported by the passage; outside knowledge or plausible inference alone is not enough.

For cloze items, test the whole sentence for grammar and meaning; a word that fits grammatically but reverses the sense is wrong.

Idioms carry fixed meanings: 'to bite the bullet' means to endure something painful, not to act aggressively.