DRDO Placement Papers 2025

Overview

This page is a working set of DRDO placement papers from 2025: from student reports questions, the 2025 online assessment pattern, and step-by-step solutions. Use it to see what DRDO actually asked in the latest cycle, how hard the rounds were, and which themes (DSA, system design, aptitude, or role-specific topics) mattered most. Practice the problems below under timed conditions, then cross-check with the interview and preparation guides if you are targeting an upcoming DRDO drive.

2025 Updates

The 2025 DRDO placement process maintains focus on technical knowledge and defence technology with enhanced emphasis on recent developments.

DRDO written examination 2025 pattern

Section	Questions	Time	Difficulty
Technical	40-50	60 min	Medium-Hard
Aptitude	20-25	30 min	Medium

DRDO Placement Papers 2025 - actual questions & solutions

This section contains practice questions styled on DRDO placement papers 2025 (recent-cycle pattern), with worked solutions. Use them as timed sectional drills - from student reports drives vary by college and role, so treat this as a high-signal practice bank, not an official paper dump.

Question 1

Q1: A train 240 m long crosses a pole in 16 seconds. Find its speed in km/h.

Solution:

Speed = distance/time = 240/16 m/s = (240/16) × (18/5) = 54 km/h.

Answer: 54 km/h

Question 2

Q2: Average of 6 numbers is 18. If one number 12 is replaced by 24, what is the new average?

Solution:

Old sum = 6 × 18 = 108. New sum = 108 − 12 + 24 = 120. New average = 120/6 = 20.

Answer: 20

Question 3

Q3: Simple interest on ₹5000 at 8% per annum for 3 years is?

Solution:

SI = (P × R × T)/100 = (5000 × 8 × 3)/100 = ₹1200.

Answer: ₹1200

Question 4

Q4: Pipe A fills a tank in 10 hours, pipe B in 15 hours. How long to fill together?

Solution:

Combined rate = 1/10 + 1/15 = (10+15)/(10×15). Time = 10×15/(10+15) = 6 hours.

Answer: 6 hours

Question 5

Q5: Which number does not belong: 10, 25, 45, 54, 60, 75, 80?

Solution:

Pattern: All divisible by 5 except 54

Odd one out = 54.

Answer: 54

Question 6

Q6: Statements: All pens are stationery. Some stationery are useful. Conclusions: I. Some pens are useful. II. All stationery are pens.

Solution:

From the statements, pens⊆stationery and some stationery overlap useful. That does not force some pens to be useful, and ‘all stationery are pens’ reverses the first statement wrongly.

Neither conclusion follows.

Answer: Neither I nor II follows

Question 7

Q7: In OOP, hiding internal details and showing only essential features is called?

Solution:

This is the definition of Encapsulation (often paired with abstraction in interviews).

Answer: Encapsulation

Question 8

Q8: Time complexity of binary search on a sorted array of n elements is?

Solution:

Each step halves the search space → O(log n).

Answer: O(log n)

Question 9: binary tree level order

Show solution

Problem Statement: Return the level-order traversal of a binary tree.

Example:

Input: [3,9,20,null,null,15,7]
Output: [[3],[9,20],[15,7]]

Solution (Java):

public List<List<Integer>> levelOrder(TreeNode root) {
    List<List<Integer>> res = new ArrayList<>();
    if (root == null) return res;
    Queue<TreeNode> q = new ArrayDeque<>();
    q.add(root);
    while (!q.isEmpty()) {
        int sz = q.size();
        List<Integer> level = new ArrayList<>();
        for (int i = 0; i < sz; i++) {
            TreeNode n = q.poll();
            level.add(n.val);
            if (n.left != null) q.add(n.left);
            if (n.right != null) q.add(n.right);
        }
        res.add(level);
    }
    return res;
}

Time Complexity: O(n)
Space Complexity: O(n)

Question 10: rotate array right by k

Show solution

Problem Statement: Rotate the array to the right by k steps.

Example:

Input: [1,2,3,4,5,6,7], k = 3
Output: [5,6,7,1,2,3,4]

Solution (Java):

public void rotate(int[] nums, int k) {
    k %= nums.length;
    reverse(nums, 0, nums.length - 1);
    reverse(nums, 0, k - 1);
    reverse(nums, k, nums.length - 1);
}
void reverse(int[] a, int l, int r) {
    while (l < r) { int t = a[l]; a[l++] = a[r]; a[r--] = t; }
}

Time Complexity: O(n)
Space Complexity: O(1)

Question 11: longest common prefix

Show solution

Problem Statement: Find the longest common prefix string amongst an array of strings.

Example:

Input: ["flower","flow","flight"]
Output: "fl"

Solution (Java):

public String longestCommonPrefix(String[] strs) {
    if (strs.length == 0) return "";
    String pref = strs[0];
    for (int i = 1; i < strs.length; i++) {
        while (!strs[i].startsWith(pref)) {
            pref = pref.substring(0, pref.length() - 1);
            if (pref.isEmpty()) return "";
        }
    }
    return pref;
}

Time Complexity: O(S)
Space Complexity: O(1)

Key insights from 2025 DRDO written examination

1. Technical Section is Critical: Must perform well in defence technology and engineering fundamentals
2. Aptitude Section: Important for overall performance
3. Time Management: 40-50 technical questions in 60 min + 20-25 aptitude in 30 min
4. Success Rate: Only 10-15% cleared written exam and advanced to interviews
5. Platform: DRDO written examination
6. Focus Areas: Defence technology, missile guidance systems, recent developments, engineering fundamentals
7. Enhanced Emphasis: Optimal solutions and recent developments knowledge

DRDO 2025 interview experiences

Based on recent candidate experiences from 2025 DRDO interviews:

2025 Interview Process:

1. Written Examination (90 minutes): Technical (40-50) + Aptitude (20-25)
2. Technical Interview (60-90 minutes): Defence technology concepts, missile guidance systems, recent developments, engineering fundamentals, problem-solving
3. HR Interview (30-45 minutes): Behavioral questions, company fit, motivation, defence technology passion

2025 Interview Trends:

• Increased emphasis on recent developments and defence technology innovations
• More focus on optimal solutions and modern defence technologies
• Enhanced behavioral questions about innovation and defence technology passion
• Questions about recent developments and defence technology applications

Common 2025 Interview Topics:

• Technical: Defence technology, missile guidance systems, recent developments, engineering fundamentals
• Aptitude: Quantitative reasoning, logical reasoning
• Behavioral: Problem-solving approach, defence technology passion, teamwork, motivation

Success Tips:

• Strong technical performance is essential - master defence technology and engineering fundamentals
• Understand missile guidance systems and recent DRDO developments
• Practice problem-solving in defence technology domain
• Prepare behavioral examples demonstrating defence technology passion
• Understand DRDO’s recent projects and defence technology programs
• Practice explaining complex technical concepts clearly

For detailed interview experiences from 2025, visit DRDO Interview Experience page.

Preparation tips for DRDO 2025 pattern

1. Master Technical Fundamentals: Focus on defence technology, missile guidance systems, recent developments - study thoroughly
2. Engineering Fundamentals: Strong understanding of engineering fundamentals relevant to defence technology
3. Practice Previous Year Papers: Solve DRDO written exam papers from 2020-2025 to understand evolving patterns
4. Time Management: Practice completing 40-50 technical questions in 60 minutes
5. Aptitude Practice: Practice quantitative and logical reasoning
6. Recent Developments: Deep understanding of DRDO’s recent developments and defence technology innovations
7. Problem-Solving: Practice solving complex technical problems in defence technology domain
8. Behavioral Preparation: Prepare examples using STAR format - defence technology passion, problem-solving
9. Mock Tests: Take timed practice tests to improve speed and accuracy
10. DRDO Projects: Stay updated with DRDO’s recent projects and defence technology programs

Comments & Suggestions

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