PERA CET flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Compound interest formula

Amount A = P(1 + R/100)^T for annual compounding, so compound interest equals A minus P. For half-yearly compounding, halve the rate and double the number of periods.

Difference CI minus SI

For two years, compound interest exceeds simple interest by P(R/100)^2, where P is principal and R the annual rate. This shortcut avoids computing both interests separately.

Successive discount formula

Two successive discounts of a% and b% equal one discount of a + b − ab/100 percent. A further discount always reduces the effective single discount below the simple sum.

Work together formula

If A alone takes x days and B alone takes y days, together they finish in xy/(x + y) days. The reciprocal of total time equals the sum of individual rates.

Downstream and upstream speeds

Downstream speed equals boat speed plus stream speed; upstream equals boat minus stream. Boat speed is the average of the two, and stream speed is half their difference.

Combination formula nCr

nCr = n!/[r!(n − r)!] counts unordered selections of r objects from n. Permutation nPr = n!/(n − r)! counts ordered arrangements, so nPr = nCr × r!.

Alligation rule

When mixing two ingredients at prices c and d to get mean price m, the quantity ratio is (m − c) : (d − m). The cheaper ingredient's share uses the dearer price difference.

Sphere and cylinder volumes

Sphere volume is (4/3)πr³ and surface area 4πr². Cylinder volume is πr²h with curved surface 2πrh. Cone volume is one-third of the cylinder with the same base and height.

Syllogism conversion rules

'Some A are B' converts to 'Some B are A', and 'No A is B' converts to 'No B is A'. 'All A are B' does not convert to 'All B are A'. Two negative premises yield no valid conclusion.

Clock hand angle

The angle between hour and minute hands is |30H − 5.5M| degrees, where H is the hour and M the minutes. The minute hand moves 6° per minute; the hour hand 0.5°.

Calendar odd days

A normal year has 1 odd day and a leap year 2. One hundred years contribute 5 odd days, and 400 years contribute 0, so the Gregorian calendar repeats every 400 years.

Direction sense turns

A right turn rotates facing 90° clockwise; a left turn rotates 90° counter-clockwise. For net displacement after perpendicular moves, use Pythagoras on the total north-south and east-west distances.

Blood relation tree method

Draw vertical lines for parent-child links and horizontal lines for siblings or marriage. Mark gender explicitly, since questions often turn on whether a person is a brother, sister, or spouse.

Circular seating orientation

In circular arrangements, clockwise order seen from one side appears anticlockwise from the opposite side. Fix one person to remove rotational symmetry before counting arrangements.

Number series strategy

Test first differences, then second differences, then ratios or squares. Alternating series often combine two patterns, so check odd and even positions separately before rejecting a rule.

Coding-decoding letter positions

Assign A = 1 through Z = 26 and compare each coded letter with its source. Frequent rules are fixed shifts, reversal (A↔Z), and position-based substitution; verify against every given pair.

Subject-verb agreement rule

Singular subjects take singular verbs; 'each', 'every', 'either', 'neither' and 'everyone' are singular. With 'neither…nor', the verb agrees with the subject nearer to it.

Present perfect tense use

Present perfect (has/have plus past participle) describes a past action with present relevance or an unfinished time period. Use past simple for finished actions with a stated past time.

Since versus for

'Since' marks a starting point in time, as in 'since 2010'. 'For' marks a duration, as in 'for three years'. Both commonly pair with perfect tenses rather than simple past.

Affect versus effect

'Affect' is usually a verb meaning to influence. 'Effect' is usually a noun meaning a result, though 'to effect' means to bring about. Choose by grammatical role in the sentence.

Between versus among

'Between' is used for two distinct items or pairwise relations; 'among' is used for more than two considered collectively. 'Between you and me' is correct because 'between' takes object pronouns.

Idiom: bite the bullet

'To bite the bullet' means to endure a painful or unpleasant situation bravely because it is unavoidable. It describes forced endurance, not a decision to attack or object.

Idiom: wild goose chase

A 'wild goose chase' is a hopeless or futile search that cannot succeed. It refers to wasted effort pursuing something unattainable, not to a fast pursuit or a hunting trip.

Reading comprehension elimination

Eliminate options that contradict the passage, overstate its claim, or rely on outside knowledge. The correct answer is supported directly by stated text or a strict inference from it.

Constitution adoption dates

The Indian Constitution was adopted on 26 November 1949 and came into force on 26 January 1950. Dr B. R. Ambedkar chaired the Drafting Committee that prepared it.

Fundamental Rights location

Fundamental Rights are in Part III of the Indian Constitution, Articles 12 to 35. Directive Principles of State Policy occupy Part IV, Articles 36 to 51, and are not directly enforceable in courts.

Right to Education amendment

Article 21A, the Right to Education, was inserted by the 86th Constitutional Amendment in 2002. It guarantees free and compulsory education to children aged six to fourteen years.

Bharat Ratna award

The Bharat Ratna is India's highest civilian award, instituted in 1954. It recognises exceptional service in any field, not only the arts, and is not restricted to Indian citizens.

UN founding details

The United Nations was founded in 1945 and has its headquarters in New York City. The World Health Organization, a UN agency, is headquartered in Geneva, Switzerland.

Tropic of Cancer in India

The Tropic of Cancer passes through eight Indian states, including Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram. It crosses India roughly midway.

Repo rate meaning

The repo rate is the interest rate at which the Reserve Bank of India lends short-term funds to commercial banks against securities. Raising it typically reduces liquidity and cools inflation.

National symbols of India

India's national bird is the peacock, the national animal is the Bengal tiger, and the national aquatic animal is the Ganges river dolphin. The national calendar is the Saka calendar.