Chandigarh Police Constable cheat sheet

Number series: check differences, then ratios, then alternating patterns (two interleaved series) before assuming a complex rule.

Coding-decoding: write the alphabet with positions 1-26; opposite-letter pairs are A-Z, B-Y, C-X (position sums always 27).

Blood relations: draw a family tree with + for male and - for female; 'only son of my grandfather' = father, 'only daughter of my mother' = sister.

Direction sense: use a cross diagram; on right turns add 90 degrees clockwise, on left turns subtract 90 degrees. Final displacement uses Pythagoras.

Syllogism: a conclusion is valid only if it holds in every possible Venn diagram of the premises; 'some' does not imply 'all' or 'no'.

Analogy and classification: identify the relation type first (part-whole, cause-effect, worker-tool, synonym, unit-measure) before matching options.

Clock: angle = |30H - 5.5M| degrees; hands coincide 11 times in 12 hours and are opposite 11 times in 12 hours.

Ranking: if a person is nth from left and mth from right, total = n + m - 1; for two persons, total = (rank1 + rank2) when ranks are from opposite ends.

Calendar: a normal year shifts the weekday by 1 day, a leap year by 2; the 100-year, 200-year and 300-year codes repeat every 400 years.

Chandigarh is a Union Territory and joint capital of Punjab and Haryana; it was designed by Le Corbusier and is divided into numbered sectors.

Punjab's five rivers of the historical Punjab region are Jhelum, Chenab, Ravi, Beas and Sutlej; only Beas and Sutlej flow through Indian Punjab today.

Articles of the Constitution: 14 equality before law, 19 six freedoms, 21 life and personal liberty, 21A right to education, 32 writs to Supreme Court, 44 uniform civil code.

Fundamental Duties are in Article 51A (Part IVA, added by the 42nd Amendment 1976); the Directive Principles are in Part IV, Articles 36-51.

Indian defence: Army Day 15 January, Navy Day 4 December, Air Force Day 8 October; the President is supreme commander of the armed forces.

National institutions: RBI founded 1935 (nationalised 1949), SEBI 1992, NITI Aayog replaced the Planning Commission on 1 January 2015.

Sports: hockey has 11 players per side, cricket 11, kabaddi 7; the Olympic flag has five rings and the modern Olympics began in 1896 at Athens.

Current affairs anchors: note the current President, Prime Minister, Chief Justice of India, RBI Governor, and Punjab/Haryana Chief Ministers and Governors, since these change frequently.

Percentage change: successive changes of a% and b% give a net change of a + b + ab/100 percent, with signs carrying the direction.

Profit and loss: SP = CP(100 + P)/100; when two articles are sold at the same price with equal gain and loss percentages, the seller always makes a net loss of (x/10)^2 percent.

Simple interest = PRT/100; compound interest = P[(1 + R/100)^T - 1]; for 2 years the CI-SI gap equals P(R/100)^2.

Time and work: if A takes a days and B takes b days, together they take ab/(a + b) days; use LCM of days as total work units.

Speed conversion: multiply km/h by 5/18 to get m/s; train crossing a platform uses length of train plus length of platform.

Boats: downstream speed = boat + stream, upstream = boat - stream; boat speed = (down + up)/2, stream speed = (down - up)/2.

Averages: new average after adding a value = (old sum + value)/(n + 1); in an arithmetic progression the average equals the middle term.

Mensuration: circle area pi r^2, circumference 2 pi r; cylinder volume pi r^2 h, curved surface 2 pi r h; sphere volume (4/3) pi r^3.

Ratio and mixture: alligation rule gives ratio of quantities = (mean price - cheaper)/(dearer - mean price); keep units consistent before applying.

English tenses: 'since' and 'for' take present perfect or present perfect continuous; 'ago' takes simple past; time clauses after 'when' do not take future tense.

Subject-verb agreement: each, every, either, neither, none, everyone are singular; 'one of the + plural noun' takes a singular verb.

Punjabi grammar: three genders (masculine, feminine, and the respectful plural form), two numbers, and direct/oblique cases; postpositions follow the noun.

Hindi grammar: two genders, two numbers, three persons; common error traps are 'ne' with transitive perfect verbs and correct use of 'ko', 'se', 'mein'.

Computer basics: 1 byte = 8 bits, 1 KB = 1024 bytes, 1 MB = 1024 KB; ROM is non-volatile, RAM is volatile and loses data on power off.

Shortcut keys: Ctrl+C copy, Ctrl+X cut, Ctrl+V paste, Ctrl+Z undo, Ctrl+Y redo, Ctrl+P print, Ctrl+S save, Ctrl+A select all, Alt+F4 close window.

File extensions: .docx Word, .xlsx Excel, .pptx PowerPoint, .pdf portable document, .jpg image, .mp3 audio, .exe executable.

Internet terms: HTTP/HTTPS protocol for web pages, URL is a web address, IP address identifies a device, email needs a valid user@domain format.

Storage order from smallest: bit, byte, KB, MB, GB, TB; a computer's CPU has ALU, control unit and registers, and is called the brain of the computer.

English idioms: 'at the drop of a hat' means immediately, 'once in a blue moon' means rarely, 'to let the cat out of the bag' means to reveal a secret.

One-word substitutions: 'philanthropist' is a lover of mankind, 'misanthrope' a hater of mankind, 'omnipotent' all-powerful, 'illegible' not readable.

Active to passive: object becomes subject, verb becomes 'be + past participle', and the agent is introduced by 'by'; keep the tense unchanged.

Punjabi script: Gurmukhi has 35 primary letters (Painti), written left to right; the vowel signs (lagan matra) attach to consonants.

Hindi script: Devanagari is written left to right; anusvara (bindu) nasalises a vowel and visarga adds a light 'h' sound.

Computer memory units: a nibble is 4 bits, a byte 8 bits; a word length is the number of bits the CPU processes at one time.

Operating system duties: process management, memory management, file management and device management; Windows, Linux and macOS are operating systems.

Network types: LAN covers a small area, WAN a large area, and the Internet is the largest WAN; a modem converts digital to analog signals and back.

Number system: divisibility by 3 or 9 depends on digit sum; by 4 on the last two digits; by 8 on the last three digits; by 11 on alternating digit sums.

HCF x LCM of two numbers equals their product; use this to find the missing value when one is known.

Simple interest doubles a sum when RT = 100; it triples when RT = 200, so time to double = 100/R years.

Partnership: profit shares are proportional to capital x time; convert all periods to the same unit before comparing.

Pipes and cisterns: a filling pipe adds rate, a draining pipe subtracts rate; net rate = sum of individual rates with signs.

Probability: P(E) = favourable outcomes / total outcomes; P(not E) = 1 - P(E); for two independent events multiply the probabilities.

Data interpretation: compute the required ratio or percentage directly from the table values rather than estimating totals first.

Simplification: apply BODMAS in order brackets, orders, division/multiplication, addition/subtraction; convert decimals to fractions for recurring patterns.

Alphabet series shortcuts: EJOTY gives positions 5, 10, 15, 20, 25 for E, J, O, T, Y; use it to locate letters quickly.

Seating arrangement: for a circle, facing centre means left is clockwise; facing outward means left is anticlockwise.

Statement and assumption: an assumption is valid only if it is necessary for the statement to make sense, not merely plausible.

Cause and effect: check whether the two statements are independent events or one plausibly produces the other before choosing.

Mirror image: left and right swap, top and bottom stay; water image: top and bottom swap, left and right stay.

Counting figures: count smallest units first, then combinations of two, three and so on, to avoid double counting.

Odd one out in numbers: test divisibility, prime/composite status, perfect squares and digit sums before choosing.

Geography of India: the Tropic of Cancer passes through eight states, and the Standard Meridian is 82 degrees 30 minutes East passing near Mirzapur.

Rivers: the Ganga rises from Gangotri, the Sutlej from Rakas Lake in Tibet, and the Beas rises near Rohtang Pass in Himachal Pradesh.

First in India: first Governor-General of independent India was Lord Mountbatten, first Indian Governor-General was C. Rajagopalachari, first President Dr Rajendra Prasad.

Science basics: the speed of light is about 3 x 10^8 m/s, the SI unit of force is the newton, and water boils at 100 degrees Celsius at sea level.

National symbols: the national bird is the peacock, national animal the Bengal tiger, national flower the lotus, national fruit the mango.

Important dates: Republic Day 26 January, Independence Day 15 August, Constitution adopted 26 November 1949 and enforced 26 January 1950.

Punjab and Haryana capitals: Chandigarh serves as the shared capital; Punjab's state animal is the blackbuck and Haryana's is the black francolin.

Percentage to fraction: 12.5% = 1/8, 16.66% = 1/6, 20% = 1/5, 25% = 1/4, 33.33% = 1/3, 50% = 1/2; memorise these for fast simplification.

If price rises by R%, consumption must fall by 100R/(100 + R) percent to keep expenditure unchanged.

Trains: time to cross a pole = train length / speed; to cross a platform = (train length + platform length) / speed.

Compound interest for 2 years at R%: amount = P(1 + R/100)^2; half-yearly compounding halves R and doubles the number of periods.

Area: triangle = 1/2 x base x height, trapezium = 1/2 (sum of parallel sides) x height, rhombus = 1/2 x product of diagonals.

Ratio of work to wages: wages are shared in the ratio of work done, which equals rate x time for each worker.

Square roots to remember: 12^2 = 144, 13^2 = 169, 14^2 = 196, 15^2 = 225, 16^2 = 256, 17^2 = 289, 18^2 = 324, 19^2 = 361, 25^2 = 625.