Aptitude
Drills
CDAC placement papers 2025
Overview
Section titled “Overview”CDAC placement papers 2025. Primary filter: CDAC Entrance / Recruitment Test. Focus: C/C++, OS, networks, aptitude.
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
Sample CDAC Questions with Solutions
Section titled “Sample CDAC Questions with Solutions”Practice-style questions (not leaked live papers).
Aptitude / Reasoning
Section titled “Aptitude / Reasoning”Q1: If 30% of x = 150, x = ?
Answer: 500
Explanation: 0.3x=150 => x=500.
Q2: Average of 5 numbers is 20. One number 30 replaced by 10. New average?
Answer: 16
Explanation: Sum 100 -> 80; avg 16.
Q3: A finishes in 10 days, B in 15. Together?
Answer: 6 days
Explanation: 1/10+1/15=1/6.
Q4: Probability of drawing an ace from a deck?
Answer: 1/13
Explanation: 4/52=1/13.
Q5: Pipe A fills in 6h, B in 8h. Together to fill?
Answer: 24/7 hours
Explanation: 1/6+1/8=7/24.
Q6: CP Rs.500, SP Rs.600. Profit percent?
Answer: 20%
Explanation: (100/500)*100=20%.
Q7: Find next: 2, 6, 12, 20, 30, ?
Answer: 42
Explanation: n(n+1) pattern.
Q8: A train 120 m long runs at 54 km/h. Time to pass a pole?
Answer: 8 seconds
Explanation: 54 km/h = 15 m/s; t = 120/15 = 8 s.
Coding Practice
Section titled “Coding Practice”Coding Q1: Top K frequent
Approach: Count + heap.
Complexity: O(n log k)
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q2: Linked list cycle
Approach: Floyd tortoise-hare.
Complexity: O(1) space
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q3: Level order traversal
Approach: BFS queue.
Complexity: O(n)
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q4: Coin change min coins
Approach: DP unbounded.
Complexity: O(amount*coins)
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q5: Binary search
Approach: Lo/hi mid.
Complexity: O(log n)
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q6: Kadane max subarray
Approach: Running best.
Complexity: O(n)
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q7: Reverse a string in-place
Approach: Two pointers from ends.
Complexity: O(n)/O(1)
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q8: Check prime
Approach: Trial division to sqrt(n).
Complexity: Handle n<2
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q9: Valid parentheses
Approach: Stack matching.
Complexity: O(n)
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Coding Q10: Two Sum
Approach: Hash map complements.
Complexity: O(n)
CDAC tip: Narrate brute force then optimize then edge cases before coding.
Deep Prep Notes for CDAC
Section titled “Deep Prep Notes for CDAC”How the CDAC Entrance / Recruitment Test Usually Feels
Section titled “How the CDAC Entrance / Recruitment Test Usually Feels”Candidates describe a paced filter where easy marks disappear if you over-invest in one hard item. For CDAC, start with a three-minute scan, mark certainty levels, and protect accuracy. Languages typically include C, C++, Java, Python.
Topic Weight Hints (Candidate-Reported)
Section titled “Topic Weight Hints (Candidate-Reported)”| Area | Why it matters at CDAC |
|---|---|
| C/C++ | Primary shortlist signal |
| Core CS (OOPs/DBMS/OS) | Technical interview depth |
| Advanced Computing R&D awareness | Managerial / HR differentiation |
| Communication | Especially for consulting and client-facing GSIs |
14-Day Sprint
Section titled “14-Day Sprint”- Days 1-3: pattern familiarization + 2 sectional mocks
- Days 4-7: weak-topic closed practice
- Days 8-10: full mocks every other day
- Days 11-14: interview narration + light revision
Related
Section titled “Related”Coding
DSA
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Assessment
Hub
CDAC