Aptitude (Quantitative & Logical) interview questions & answers
Aptitude tests measure quantitative and logical reasoning ability through timed problems on arithmetic, ratios, probability, number series, and verbal logic. They are a common first-round filter at large employers and campus placements because they predict problem-solving speed under pressure. Success comes from knowing standard methods and shortcuts rather than memorizing answers.
Updated 2026-06-18 · 15 real, commonly-asked questions with answers.
Key takeaways
- Aptitude tests measure quantitative and logical reasoning ability through timed problems on arithmetic, ratios, probability, number series, and verbal logic.
- Core areas to revise for Aptitude (Quantitative & Logical): Arithmetic (percentages, profit/loss), Time, speed & work, Ratio & proportion, Probability & combinatorics, Number series.
- This guide answers 15 of the most-asked Aptitude (Quantitative & Logical) interview questions — rehearse them in OnJob's free AI mock interview.
Top 15 Aptitude (Quantitative & Logical) interview questions
Q1.Time and Work: A can do a job in 10 days and B in 15 days. How long together?
Convert to per-day rates: A does 1/10 of the work per day and B does 1/15. Together they do 1/10 plus 1/15 = 3/30 plus 2/30 = 5/30 = 1/6 per day. So they finish in 6 days.
Q2.Percentages: If a price rises 20% then falls 20%, what is the net change?
Take 100 as the base. A 20% rise gives 120, then a 20% fall on 120 removes 24, leaving 96. So the net effect is a 4% decrease, because successive percentage changes apply to different bases.
Q3.Profit and Loss: An item bought for 400 is sold for 500. What is the profit percent?
Profit equals selling price minus cost price = 500 minus 400 = 100. Profit percent is profit divided by cost price, times 100 = 100/400 times 100 = 25%. Always compute profit percent on cost price unless stated otherwise.
Q4.Ratio and Proportion: Divide 600 between A and B in the ratio 2:3.
Add the ratio parts: 2 plus 3 = 5 total parts. Each part is 600 divided by 5 = 120. So A gets 2 parts = 240 and B gets 3 parts = 360.
Q5.Simple vs Compound Interest: Find SI and CI on 1000 at 10% for 2 years.
Simple interest is principal times rate times time divided by 100 = 1000 times 10 times 2 / 100 = 200. Compound interest is principal times (1.1 to the power 2) minus principal = 1210 minus 1000 = 210. CI exceeds SI by 10, the interest earned on the first year's interest.
Q6.Average: The average of 5 numbers is 20. If one number 30 is removed, what is the new average?
Total of 5 numbers is 5 times 20 = 100. Removing 30 leaves a sum of 70 across 4 numbers. The new average is 70 divided by 4 = 17.5.
Q7.Speed, Distance, Time: A train 200 m long passes a pole in 10 seconds. Find its speed.
To pass a pole the train covers its own length, 200 m, in 10 s. Speed is distance divided by time = 200/10 = 20 m/s. Multiply by 3.6 to convert to km/h: 20 times 3.6 = 72 km/h.
Q8.Probability: A bag has 3 red and 2 blue balls. What is the probability of drawing a red ball?
Probability is favorable outcomes divided by total outcomes. There are 3 red balls out of 5 total, so the probability of red is 3/5 = 0.6. This assumes each ball is equally likely to be drawn.
Q9.Number Series: Find the next term: 2, 6, 12, 20, 30, ?
Look at the differences: 4, 6, 8, 10, which increase by 2 each time. The next difference is 12, so the next term is 30 plus 12 = 42. Equivalently each term is n times (n plus 1): 1 times 2, 2 times 3, 3 times 4, and so on.
Q10.Permutations and Combinations: In how many ways can 3 books be arranged on a shelf?
Arranging distinct items in order is a permutation, given by factorial. For 3 books it is 3 factorial = 3 times 2 times 1 = 6 ways. If order did not matter it would be a single combination instead.
Q11.Ages: A father is 3 times as old as his son. In 12 years he will be twice as old. Find their ages.
Let the son be x; the father is 3x. In 12 years: 3x plus 12 = 2 times (x plus 12), so 3x plus 12 = 2x plus 24, giving x = 12. The son is 12 and the father is 36.
Q12.Mixtures: How much water must be added to 60 L of milk to make it 40% water?
After adding water, milk stays 60 L and should be 60% of the mixture. So total = 60 divided by 0.6 = 100 L. Water added is 100 minus 60 = 40 L.
Q13.Syllogism: All cats are animals. Some animals are wild. Does it follow that some cats are wild?
No. The first statement places all cats inside animals, but the wild animals mentioned need not include any cats. Without a guaranteed overlap, the conclusion does not necessarily follow, so it is invalid.
Q14.Coding-Decoding: If CAT is coded as DBU, how is DOG coded?
Each letter is shifted forward by one position in the alphabet (C to D, A to B, T to U). Applying the same shift to DOG gives E, P, H. So DOG is coded as EPH.
Q15.Pipes and Cisterns: One pipe fills a tank in 6 hours, another empties it in 12 hours. Time to fill if both open?
The filling pipe adds 1/6 per hour and the emptying pipe removes 1/12 per hour. Net rate is 1/6 minus 1/12 = 2/12 minus 1/12 = 1/12 per hour. So the tank fills in 12 hours.
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