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UPSC Civil Services Exam (CSE) CSAT (Prelims Paper-II): Aptitude and Reasoning Flashcards
51 question-and-answer cards covering CSAT (Prelims Paper-II): Aptitude and Reasoning as it is examined in UPSC Civil Services Exam (CSE). 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the CSAT (Prelims Paper-II): Aptitude and Reasoning deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
What is the only even prime number, and why?
2 is the only even prime number, because every other even number is divisible by 2 (in addition to 1 and itself), giving it more than two factors.
State the relationship between the LCM and HCF of two numbers.
For two numbers a and b: LCM × HCF = a × b. (The product of the two numbers equals the product of their LCM and HCF.)
What are co-prime (relatively prime) numbers?
Two numbers are co-prime if their highest common factor (HCF) is 1, meaning they share no common factor other than 1 (e.g., 8 and 15).
State the divisibility rule for 3 and for 9.
A number is divisible by 3 if the sum of its digits is divisible by 3; it is divisible by 9 if the sum of its digits is divisible by 9.
State the divisibility rule for 11.
A number is divisible by 11 if the difference between the sum of digits at odd places and the sum of digits at even places is 0 or a multiple of 11.
What does 'order of magnitude' mean, and how do two quantities differ by one order of magnitude?
Order of magnitude is the approximate size of a number expressed as a power of 10. Two quantities differ by one order of magnitude when one is about 10 times the other.
What is the formula for simple interest?
Simple Interest (SI) = (P × R × T) / 100, where P = principal, R = rate of interest per annum, and T = time in years.
What is the formula for compound interest (amount) compounded annually?
Amount A = P(1 + R/100)^T, where P = principal, R = annual rate, T = time in years; Compound Interest = A − P.
How do you convert a fraction or ratio into a percentage?
Multiply the fraction (or ratio value) by 100. For example, 3/4 = (3/4) × 100 = 75%.
What is the formula for percentage profit on cost price?
Profit % = (Profit / Cost Price) × 100, where Profit = Selling Price − Cost Price.
State the basic relationship among speed, distance, and time.
Speed = Distance / Time. Equivalently, Distance = Speed × Time and Time = Distance / Speed.
How do you convert a speed from km/h to m/s?
Multiply by 5/18. (km/h × 5/18 = m/s; conversely m/s × 18/5 = km/h.)
What is the formula for the average of a set of numbers?
Average (mean) = (Sum of all observations) / (Number of observations).
What is the formula for the area and perimeter of a rectangle?
Area = length × breadth; Perimeter = 2 × (length + breadth).
What is the formula for the area and circumference of a circle?
Area = πr² and Circumference = 2πr, where r is the radius and π ≈ 22/7 or 3.14.
State the Pythagoras theorem for a right-angled triangle.
In a right-angled triangle, the square of the hypotenuse equals the sum of the squares of the other two sides: hypotenuse² = base² + perpendicular².
How is the nth term of an arithmetic progression (AP) calculated?
The nth term aₙ = a + (n − 1)d, where a is the first term and d is the common difference.
What is the formula for the sum of the first n terms of an arithmetic progression?
Sₙ = n/2 × [2a + (n − 1)d], or equivalently Sₙ = n/2 × (first term + last term).
What is the formula for permutations of n distinct items taken r at a time?
ⁿPᵣ = n! / (n − r)!, used when order matters.
What is the formula for combinations of n distinct items taken r at a time?
ⁿCᵣ = n! / [r! (n − r)!], used when order does not matter.
What is the basic formula for the probability of an event?
Probability = (Number of favourable outcomes) / (Total number of possible outcomes), and its value always lies between 0 and 1 inclusive.
In data interpretation, what is the difference between a 'bar graph' and a 'pie chart'?
A bar graph uses rectangular bars whose lengths represent values, good for comparing categories; a pie chart uses sectors of a circle to show each part as a proportion of the whole (totalling 100% or 360 degrees).
In a pie chart, how do you convert a percentage share into the central angle of its sector?
Central angle = (Percentage / 100) × 360 degrees. Equivalently, each 1% corresponds to 3.6 degrees of the circle.
In statistics, define the mean, median, and mode of a data set.
Mean is the arithmetic average (sum ÷ count); median is the middle value when data are arranged in order; mode is the value that occurs most frequently.
What this deck covers
The CSAT (Prelims Paper-II): Aptitude and Reasoning deck follows the UPSC Civil Services Exam (CSE) CSAT (Prelims Paper-II): Aptitude and Reasoning syllabus — 4 chapters and 13 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 12.8 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 110 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
CSAT (Prelims Paper-II): Aptitude and Reasoning flashcards FAQ
How many CSAT (Prelims Paper-II): Aptitude and Reasoning flashcards are in this UPSC Civil Services Exam (CSE) deck?
51 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these UPSC Civil Services Exam (CSE) flashcards free?
Yes. The preview here is free to read with no signup, and the full 51-card deck is free inside the Examius app.
What do the CSAT (Prelims Paper-II): Aptitude and Reasoning cards cover?
They follow the UPSC Civil Services Exam (CSE) CSAT (Prelims Paper-II): Aptitude and Reasoning syllabus — 4 chapters and 13 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.