Preparation guide
CDAC Aptitude Questions
Overview
This page has CDAC aptitude questions with full solutions - numerical ability, verbal, and logical reasoning - in the style students report for the CDAC Entrance / Recruitment Test. Start with the timed mock quiz, then work the solved set and log every miss by topic.
CDAC 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
Quantitative
Successive discounts of 20% and 10% are equivalent to a single discount of:
Effective = 100 − 80×90/100 = 28%.
Reasoning
Find the next number: 2, 6, 12, 20, 30, ?
Differences +4, +6, +8, +10, +12 → next is 42.
Quantitative
Six people A, B, C, D, E, F are sitting around a circular table. A is opposite to D. B is between A and C. E is not adjacent to A. Who is sitting opposite to E?
In circular arrangement with 6 people, opposite pairs are: (A,D), (B,E), (C,F) Since A is opposite D, and B is between A and C, and E is not adjacent to A E must be opposite B
Quantitative
The ratio of two numbers is 3:4. If their sum is 84, find the numbers.
Let the numbers be 3x and 4x Sum = 3x + 4x = 7x = 84 x = 12 Numbers = 3(12) = 36 and 4(12) = 48
Reasoning
Find the next number: 2, 5, 11, 23, 47, ?
Pattern: Each number = previous × 2 + 1 2×2+1=5, 5×2+1=11, 11×2+1=23, 23×2+1=47 Next: 47×2+1 = 95
Reasoning
Two trains of lengths 120m and 180m are running in opposite directions at speeds of 40 km/hr and 50 km/hr respectively. Find the time taken to cross each other.
Relative speed = 40 + 50 = 90 km/hr = 90 × 5/18 = 25 m/s Total distance = 120 + 180 = 300m Time = 300/25 = 12 seconds
Verbal
"Break the ice" means:
It means to initiate conversation in a social setting.
Quantitative
A cube, painted yellow on all faces is cut into 27 small cubes of equal size. How many small cubes are painted on one face only?
Correct answer: 6
Quantitative
Find the compound interest on ₹5000 for 2 years at 10% per annum, compounded annually.
Correct answer: ₹1050
Quantitative
A person travels first half of distance at 40 km/hr and second half at 60 km/hr. Find average speed.
Let total distance = 2D Time for first half = D/40 Time for second half = D/60 Total time = D/40 + D/60 = D(3+2)/120 = 5D/120 = D/24 Average speed = 2D / (D/24) = 48 km/hr
Verbal
Choose the correct synonym for "Ephemeral":
"Ephemeral" means lasting for a very short time, temporary. "Temporary" is the synonym.
Verbal
Antonym of "Temporary":
Temporary ↔ permanent.
Reasoning
In a row of 30 students, A is 10th from the left. Rank from the right is:
From right = 30-10+1 = 21.
Verbal
One who loves books is a:
Bibliophile = lover of books.
Reasoning
Arrange the words: 1. Elephant 2. Cat 3. Dog 4. Ant
Correct answer: 4, 2, 3, 1
Your score
0/15(0%)
Review
CDAC 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: Worker scaling
Problem: Eight workers finish a job in 10 days. How many days will 10 workers take for the same job (same pace)?
Solution: Total man-days = 8 × 10 = 80. Days for 10 workers = 80 / 10 = 8 days.
Answer: 8 days
Q2: Percentage recover
Problem: If 30% of a number is 150, what is the number?
Solution: 0.3x = 150 → x = 150 / 0.3 = 500.
Answer: 500
Q3: A and B together
Problem: A can finish a job in 10 days and B in 20 days. How long will they take working together?
Solution: A’s one-day work = 1/10. B’s one-day work = 1/20. Together = 1/10 + 1/20 = 3/20 per day. Time = 20/3 ≈ 6.67 days (6 days 16 hours).
Answer: 20/3 days
Q4: Speed convert
Problem: Convert 18 m/s to km/h.
Solution: Multiply by 18/5: 18 × 18/5 = 64.8 km/h.
Answer: 64.8 km/h
Q5: Algebra ages
Problem: Father is 3 times as old as son. After 12 years he will be twice as old. Son’s present age?
Solution: 3x + 12 = 2(x + 12) → 3x + 12 = 2x + 24 → x = 12.
Answer: 12 years
Q6: Train platforms
Problem: A 200 m train at 72 km/h crosses a 160 m platform. Time taken?
Solution: Speed = 72 × 5/18 = 20 m/s. Distance = 200+160 = 360 m. Time = 360/20 = 18 s.
Answer: 18 seconds
Q7: Permutation basic
Problem: In how many ways can 5 different books be arranged on a shelf?
Solution: Arrangements of 5 distinct items = 5! = 120.
Answer: 120
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: Compound ratio
Problem: If two ratios are 3:5 and 5:7, what is the compound ratio?
Solution: Compound ratio = (3/5) × (5/7) = 3/7, written as 3:7.
Answer: 3:7
Q10: SI three years
Problem: Find simple interest on ₹5000 at 8% per annum for 3 years.
Solution: SI = 5000 × 8 × 3 / 100 = ₹1200.
Answer: ₹1200
Verbal ability questions
Q11: Phrase - by and large
Problem: Meaning of ‘by and large’?
Solution: Generally / on the whole.
Answer: Generally
Q12: Antonym - opaque
Problem: Choose the best antonym of ‘opaque’.
Solution: ‘Opaque’ means not transparent. Opposite: transparent / clear.
Answer: Transparent
Q13: Synonym - abundant
Problem: Choose the best synonym of ‘abundant’.
Solution: ‘Abundant’ means present in large quantity. Closest match: plentiful.
Answer: Plentiful
Q14: Synonym - mitigate
Problem: Choose the best synonym of ‘mitigate’.
Solution: ‘Mitigate’ means to make less severe. Closest match: alleviate.
Answer: Alleviate
Q15: Antonym - benevolent
Problem: Choose the best antonym of ‘benevolent’.
Solution: ‘Benevolent’ means kind or well-meaning. Opposite: malevolent.
Answer: Malevolent
Q16: Fill in the blank
Problem: She _____ to the office every day by metro. (go / goes / going / gone)
Solution: Third-person singular present needs ‘goes’.
Answer: goes
Reasoning ability questions
Q17: Blood relation
Problem: Pointing to a photograph, Ravi says, ‘She is the daughter of my mother’s only son.’ How is the girl related to Ravi?
Solution: Ravi’s mother’s only son is Ravi himself (assuming one son). The girl is therefore Ravi’s daughter.
Answer: Daughter
Q18: 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
Q19: Statement assumption
Problem: Statement: Use public transport to reduce pollution. Assumption: Public transport causes less pollution than private vehicles.
Solution: The advice assumes public transport is cleaner. Assumption is implicit.
Answer: Implicit / valid
Q20: Direction return
Problem: You walk 2 km east, 3 km south, 2 km west. How far from start?
Solution: East/west cancel; 3 km south from start.
Answer: 3 km south
Q21: 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
Q22: Coding letter shift
Problem: If CAT is coded as DBU, how is DOG coded in the same way?
Solution: Each letter moves +1 in the alphabet: C→D, A→B, T→U. D→E, O→P, G→H → EPH.
Answer: EPH
Timed practice tips for CDAC
- 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