ONGC 2025 aptitude
Quantitative, reasoning, and verbal drills with solutions
This page collects ONGC placement papers from 2025 with practice questions, worked solutions, and the exam pattern students reported that cycle. Use it when you want drive history: what the first round looked like, which topics repeated, and how to approach solutions. Work the sets below under a timer, then compare with newer material so your prep matches both established ONGC patterns and recent shifts.
ONGC 2025 aptitude
Quantitative, reasoning, and verbal drills with solutions
ONGC 2025 coding
DSA practice aligned to ONGC online assessments
ONGC interview experience
Round structure and tips from student reports
ONGC prep guide
Study plan and weekly schedule
Timed placement-style MCQs with score and explanations after you submit. Use it to check speed and accuracy before the real test.
Quantitative
Pointing to a photograph, a man said, "She is the daughter of my grandfather's only son." How is the man related to the person in the photograph?
Grandfather's only son = man's father Daughter of man's father = man's sister So the person is the man's sister
Quantitative
The average of 5 numbers is 20. If one number is removed, the average becomes 18. Find the removed number.
Correct answer: 28
Reasoning
All roses are flowers. Some flowers fade quickly. Conclusion: All roses fade quickly.
Only some flowers.
Verbal
Identify the correctly spelled word:
Accommodate has double "c" and double "m".
Quantitative
If the perimeter of a rectangle is 60 cm and its length is twice its breadth, find the area of the rectangle.
Let breadth = x cm, length = 2x cm Perimeter = 2(length + breadth) = 2(2x + x) = 6x = 60 x = 10 cm Length = 20 cm, Breadth = 10 cm Area = 20 × 10 = 200 cm²
Verbal
Choose the correct synonym for "Ephemeral":
"Ephemeral" means lasting for a very short time, temporary. "Temporary" is the synonym.
Reasoning
Odd one out: 121, 144, 169, 196, 225
Others are odd squares.
Quantitative
A, B, and C can complete a work in 10, 15, and 20 days respectively. If they work together, in how many days will they complete the work?
Correct answer: 4.62 days
Reasoning
A person walks 5 km north, then 3 km east, then 2 km south. How far and in which direction is he from the starting point?
Net north = 5 - 2 = 3 km Net east = 3 km Distance = √(3² + 3²) = √18 = 3√2 km Direction = Northeast
Verbal
Problem: "She is good _____ mathematics." a) at b) in c) on d) with
"Good at" is the correct prepositional phrase for skills.
Verbal
Synonym of "Meticulous":
Meticulous means detailed.
Reasoning
Odd one out: 8, 27, 64, 100, 125
Others are perfect cubes; 100 is not.
Reasoning
Odd one out: Triangle, Square, Circle, Rectangle
Circle has no straight sides.
Quantitative
Reading Comprehension - Main Idea (2025)
Correct answer: Renewable energy and its growing importance
Quantitative
If 3x + 5 = 20, then x equals:
3x = 15 → x = 5.
Your score
0/15(0%)
| Section | What shows up | Prep focus |
|---|---|---|
| Technical / domain | Syllabus aligned to the notification | Topic checklist |
| Aptitude | Quant + reasoning | Speed with accuracy |
| Interview | Subject depth + projects | Clear fundamentals |
First round: ONGC GATE-based Recruitment
Skills emphasized: GATE technical, interview
Languages: N/A for core
These are practice-style questions aligned to patterns students report for ONGC drives around 2025. They are not leaked live papers. Work them timed, then read the solutions only after you have an answer.
Problem: Find simple interest on ₹5000 at 8% per annum for 3 years.
Solution: SI = 5000 × 8 × 3 / 100 = ₹1200.
Answer: ₹1200
Problem: A boat’s speed in still water is 15 km/h and the stream is 3 km/h. How long to cover 36 km upstream?
Solution: Upstream speed = 15 − 3 = 12 km/h. Time = 36 / 12 = 3 hours.
Answer: 3 hours
Problem: A mixture has milk and water in the ratio 4:1. If 5 litres of water are added to 20 litres of mixture, what is the new milk:water ratio?
Solution: In 20 L: milk = 16 L, water = 4 L. After adding 5 L water: milk 16, water 9. Ratio = 16:9.
Answer: 16:9
Problem: Find compound interest on ₹10,000 at 10% per annum for 2 years, compounded annually.
Solution: Amount = 10000 × (1.1)² = 10000 × 1.21 = ₹12,100. CI = 12100 − 10000 = ₹2100. (SI for same period would be ₹2000; the extra ₹100 is interest on first-year interest.)
Answer: ₹2100
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°
Problem: In how many ways can 5 different books be arranged on a shelf?
Solution: Arrangements of 5 distinct items = 5! = 120.
Answer: 120
Problem: If the sum of three consecutive integers is 72, what is the smallest of these integers?
Solution: Let the integers be x, x+1, and x+2.
x + (x+1) + (x+2) = 72 3x + 3 = 72 3x = 69 x = 23
So the integers are 23, 24, and 25.
Answer: 23
Problem: A train 150 meters long passes a pole in 15 seconds. What is its speed in km/h?
Solution: Distance = 150 m = 0.15 km. Time = 15 s = 15/3600 h = 1/240 h. Speed = 0.15 ÷ (1/240) = 0.15 × 240 = 36 km/h.
Faster check: 150/15 = 10 m/s → 10 × 18/5 = 36 km/h.
Answer: 36 km/h
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
Problem: Book is to Reading as Fork is to ?
Solution: A book is used for reading; a fork is used for eating.
Answer: Eating
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
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
Problem: Given the head of a linked list, return true if there is a cycle and false otherwise.
Approach: Floyd’s tortoise and hare: move one pointer one step and another two steps. If they meet, a cycle exists. If the fast pointer hits null, there is no cycle.
Complexity: O(n) time, O(1) space
ONGC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Problem: Given the root of a binary tree, return the level-order traversal (breadth-first) as a list of levels.
Approach: Use a queue. For each level, drain the current queue size, collect values, and enqueue children for the next level.
Complexity: O(n) time, O(n) space
ONGC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Problem: Given coin denominations and an amount, return the fewest coins needed to make that amount, or -1 if it is impossible.
Approach: Unbounded knapsack DP: let dp[x] be the minimum coins for amount x. For each coin, update dp[c..amount]. Initialize dp[0] = 0 and the rest to a large sentinel.
Complexity: O(amount × coins)
ONGC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Problem: Given a sorted array of distinct integers and a target, return the index of target or -1 if missing.
Approach: Maintain lo/hi. Compare mid with target and shrink the half that cannot contain it. Careful with overflow-free mid and empty arrays.
Complexity: O(log n) time
ONGC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Problem: Move all zeros in an array to the end while keeping the relative order of non-zero elements.
Approach: Two pointers: write non-zeros toward the front, then fill the remainder with zeros. Or swap zeros as you scan.
Complexity: O(n) time, O(1) space
ONGC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Problem: Rotate an array to the right by k steps. Example: [1,2,3,4,5,6,7], k = 3 → [5,6,7,1,2,3,4].
Approach: Normalize k %= n. Reverse the whole array, reverse the first k elements, then reverse the rest. That yields the rotation in place.
Complexity: O(n) time, O(1) space
ONGC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Problem: Find the first non-repeating character in a string and return its index, or -1 if none exists.
Approach: Count frequencies in one pass (hash map or array of 26 for lowercase). Second pass returns the first index with count 1.
Complexity: O(n) time
ONGC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Problem: Design a stack that supports push, pop, top, and getMin in average O(1) time.
Approach: Keep a parallel min-stack (or store pairs). When pushing, also push the new minimum. When popping, pop both stacks.
Complexity: O(1) per operation amortized
ONGC tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Students usually say the first round is time-tight - easy marks vanish if you sit too long on one hard question. For ONGC, skim the paper in a couple of minutes, mark what you can finish cleanly, and protect accuracy. Languages people commonly use: N/A for core.
| Area | Why it matters at ONGC |
|---|---|
| GATE technical | What usually helps you clear the first round |
| Core CS (OOPs / DBMS / OS) | Technical interview depth |
| Oil & Gas Exploration PSU awareness | Helps in managerial / HR conversations |
| Communication | Explain your approach clearly; keep a few real examples ready for HR |