Preparation guide
DRDO Aptitude Questions
Overview
This page has DRDO aptitude questions with full solutions - numerical ability, verbal, and logical reasoning - in the style students report for the DRDO Online Assessment. Start with the timed mock quiz, then work the solved set and log every miss by topic.
DRDO Aptitude Mock Quiz
Timed placement-style MCQs with score and explanations after you submit. Use it to check speed and accuracy before the real test.
Questions15
Time10 min
Verbal
"To add fuel to the fire" means:
It means worsening a conflict or situation.
Quantitative
Select 3 people from 10 for a committee. How many ways?
Correct answer: C(10,3) = 10!/(3!×7!) = 120
Quantitative
Find compound interest on ₹5,000 for 1 year at 10% per annum, compounded half-yearly.
Rate per half year = 10/2 = 5% Number of periods = 2 Amount = 5000(1 + 5/100)² = 5000 × 1.05² = 5000 × 1.1025 = ₹5,512.50 CI = 5,512.50 - 5,000 = ₹512.50
Quantitative
A can do a job in 10 days, B in 15. Days together:
1/10+1/15=1/6 → 6 days.
Reasoning
In how many ways can 5 people be arranged in a row if two particular people must sit together?
Treat the two people as one unit: 4 units to arrange = 4! ways The two people can be arranged among themselves in 2! ways Total = 4! × 2! = 24 × 2 = 48 ways
Reasoning
Find the next number: 1, 3, 6, 10, 15, ?
Correct answer: 21
Quantitative
Choose the improved version: "The data shows that the company's profits have increased."
"Data" can be singular or plural, but "shows" (singular) is commonly accepted. Option a uses plural verb which is also correct.
Verbal
Fill in: She is good _____ mathematics.
Good at a subject.
Quantitative
Pointing to a photograph, a man says, "She is the daughter of my grandfather's only son." How is the girl related to the man?
The man's grandfather's only son = the man's father Daughter of the man's father = the man's sister Therefore, the girl is the man's sister.
Reasoning
Statements: 1. Some books are novels, 2. All novels are stories, 3. No story is a poem
From 1 and 2: Some books are stories (I follows) From 2 and 3: No novel is a poem (II follows) From I: Some stories are books (III follows)
Verbal
A tap fills a tank in 5 hours, and another tap empties it in 7 hours. How long will it take to fill the tank if both taps are open?
Filling tap fills 1/5 of tank per hour Emptying tap empties 1/7 of tank per hour Net filling = 1/5 - 1/7 = (7-5)/35 = 2/35 per hour Time to fill = 1 / (2/35) = 35/2 = 17.5 hours
Reasoning
Statements: 1. All green are blue, 2. All blue are white
From "All green are blue": Some blue are green (I follows) Combined: All green are white, so Some white are green (II follows) and Some green are white (III follows) IV does not follow
Quantitative
A and B finish a job in 12 and 18 days. Working together they finish in:
1/12 + 1/18 = 5/36 → 36/5 = 7.2 days.
Verbal
Synonym of "Abundant":
Abundant means plentiful.
Reasoning
Odd one out: Rose, Lily, Lotus, Leaf
Others are flowers.
Your score
0/15(0%)
Review
DRDO aptitude topics students usually practice
- Numerical / quantitative: percentages, profit and loss, ratios, time and work, averages, SI/CI, speed-distance
- Logical reasoning: series, coding-decoding, blood relations, seating, syllogisms
- Verbal ability: grammar, vocabulary, error spotting, idioms
Numerical ability questions
Q1: Work efficiency
Problem: A is twice as efficient as B. Together they finish in 12 days. How many days does A alone need?
Solution: Let B = x days, A = x/2. 1/(x/2) + 1/x = 1/12 → 2/x + 1/x = 1/12 → 3/x = 1/12 → x = 36. A alone = 18 days.
Answer: 18 days
Q2: Relative speed trains
Problem: Two trains 120 m and 180 m long run at 40 and 50 km/h in opposite directions. Time to cross?
Solution: Relative speed = 90 km/h = 25 m/s. Distance = 300 m. Time = 12 s.
Answer: 12 seconds
Q3: Profit false weight
Problem: A seller uses 900 g weight for 1 kg and sells at cost price. Profit %?
Solution: Buys 900, sells as 1000 at CP. Profit = 100/900 × 100 ≈ 11.11%.
Answer: 11.11%
Q4: Alligation milk
Problem: Milk at ₹40/L and ₹50/L mixed to get ₹44/L. Ratio of quantities?
Solution: Alligation: (50−44):(44−40) = 6:4 = 3:2.
Answer: 3:2
Q5: Profit on a pen
Problem: If the cost price of a pen is ₹40 and it is sold at a 25% profit, what is the selling price?
Solution: Profit = 25% of 40 = ₹10. Selling price = 40 + 10 = ₹50.
Or SP = CP × 1.25 = 40 × 1.25 = ₹50.
Answer: ₹50
Q6: Age ratio
Problem: The ratio of ages of A and B is 3:5. After 8 years the ratio becomes 5:7. Find A’s present age.
Solution: Let ages be 3x and 5x. (3x+8)/(5x+8) = 5/7 7(3x+8) = 5(5x+8) 21x + 56 = 25x + 40 4x = 16 → x = 4 A’s age = 12 years.
Answer: 12 years
Q7: Deck probability
Problem: What is the probability of drawing an ace from a standard 52-card deck?
Solution: There are 4 aces in 52 cards. Probability = 4/52 = 1/13.
Answer: 1/13
Q8: Distance from speed
Problem: A vehicle travels at 60 km/h for 2.5 hours. How far does it go?
Solution: Distance = speed × time = 60 × 2.5 = 150 km.
Answer: 150 km
Q9: Clock angle
Problem: What is the angle between the hour and minute hands at 3:00?
Solution: At 3:00 the hands are exactly 90° apart (one quarter of the circle).
Answer: 90°
Q10: LCM HCF product
Problem: Two numbers have HCF 12 and LCM 180. If one number is 36, find the other.
Solution: Product of numbers = HCF × LCM. 36 × other = 12 × 180 = 2160. Other = 2160 / 36 = 60.
Answer: 60
Verbal ability questions
Q11: One word - extinct
Problem: A species that no longer exists is?
Solution: Extinct.
Answer: Extinct
Q12: Antonym - benevolent
Problem: Choose the best antonym of ‘benevolent’.
Solution: ‘Benevolent’ means kind or well-meaning. Opposite: malevolent.
Answer: Malevolent
Q13: Antonym - opaque
Problem: Choose the best antonym of ‘opaque’.
Solution: ‘Opaque’ means not transparent. Opposite: transparent / clear.
Answer: Transparent
Q14: Sentence rearrange
Problem: Arrange: (1) the exam (2) she cleared (3) with ease
Solution: She cleared the exam with ease.
Answer: 2-1-3
Q15: Error spotting
Problem: Spot the error: ‘Neither of the boys have submitted their assignment.’
Solution: ‘Neither’ is singular, so the verb should be ‘has’ (and ideally ‘his’ / ‘their’ per style guide). Correct: Neither of the boys has submitted his assignment.
Answer: have → has
Q16: Error spotting subject
Problem: Identify the error: The list of items are on the table.
Solution: ‘List’ is singular → ‘is’ not ‘are’.
Answer: are → is
Reasoning ability questions
Q17: Input output step
Problem: Input: 34 12 57 23. Step1 sorts ascending: 12 23 34 57. What is Step1 third element?
Solution: Sorted: 12, 23, 34, 57. Third = 34.
Answer: 34
Q18: Seating hint
Problem: Five friends sit in a row. A is to the left of B but right of C. D is to the right of B and left of E. Who is in the middle?
Solution: Order from left to right: C, A, B, D, E. The middle seat is B.
Answer: B
Q19: Odd one shapes
Problem: Odd one out: Circle, Square, Triangle, Cube
Solution: Cube is 3D; others are 2D shapes.
Answer: Cube
Q20: Odd one out
Problem: Find the odd one out: 3, 5, 7, 9, 11
Solution: 3, 5, 7, and 11 are prime. 9 = 3×3 is composite, so it is the odd one out.
Answer: 9
Q21: Coding opposite
Problem: If ROAD is coded as URDG, how is RACE coded?
Solution: Each letter +3: R→U, O→R, A→D, D→G. R→U, A→D, C→F, E→H → UDFH.
Answer: UDFH
Q22: Puzzle order
Problem: P finishes before Q but after R. S finishes after Q. Who finished first?
Solution: Order: R, P, Q, S. First is R.
Answer: R
Timed practice tips for DRDO
- First pass: only high-confidence questions
- Mark and skip time sinks early
- Keep verbal accuracy high - these are easy marks if you stay calm
- Run the mock quiz at least three times a week under real timing
- Sleep properly the night before; fatigue hurts DI and calculation accuracy