ISRO Placement Papers 2025

Overview

This page is a working set of ISRO placement papers from 2025: from student reports questions, the 2025 online assessment pattern, and step-by-step solutions. Use it to see what ISRO 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 ISRO drive.

2025 Updates

The 2025 ISRO placement process maintains focus on technical knowledge and space technology with enhanced emphasis on recent missions and innovations.

ISRO written examination 2025 pattern

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

ISRO Placement Papers 2025 - actual questions & solutions

This section contains practice questions styled on ISRO 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 number is increased by 20% and then decreased by 20%. Find the net percentage change.

Solution:

Let original = 100. After +20% → 120. After −20% → 120 − 24 = 96.

Net change = 100 − 96 = 4. Net % = 4% decrease (always a loss of (20/10)² %).

Answer: 4% decrease

Question 2

Q2: Average of 5 numbers is 20. If one number 15 is replaced by 25, what is the new average?

Solution:

Old sum = 5 × 20 = 100. New sum = 100 − 15 + 25 = 110. New average = 110/5 = 22.

Answer: 22

Question 3

Q3: A and B together finish a job in 8 days. B alone takes 24 days. How many days does A alone take?

Solution:

Together rate = 1/8. B’s rate = 1/24.

A’s rate = 1/8 − 1/24 = (24−8)/(8×24) = 16/192. Days for A alone = 192/16 = 12 days.

Answer: 12 days

Question 4

Q4: Pipe A fills a tank in 12 hours, pipe B in 18 hours. How long to fill together?

Solution:

Combined rate = 1/12 + 1/18 = (12+18)/(12×18). Time = 12×18/(12+18) = 7.2 hours.

Answer: 7.2 hours

Question 5

Q5: In a row of 43 students, A is 9th from the left and B is 14th from the right. How many students are between A and B if A is to the left of B?

Solution:

Positions from left: A = 9, B = 43 − 14 + 1 = 30. Students between = 30 − 9 − 1 = 20.

Answer: 20

Question 6

Q6: Find the next number in the series: 5, 10, 20, 40, ?

Solution:

Pattern: Each term ×2

Next term = 80.

Answer: 80

Question 7

Q7: 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 8

Q8: Which SQL clause filters grouped rows after GROUP BY?

Solution:

HAVING filters aggregates; WHERE filters rows before grouping.

Answer: HAVING

Question 9: valid parentheses

Show solution

Problem Statement: Given a string of brackets, determine if it is valid.

Example:

Input: "()[]{}"
Output: true

Solution (Java):

public boolean isValid(String s) {
    Deque<Character> st = new ArrayDeque<>();
    Map<Character, Character> pair = Map.of(')', '(', ']', '[', '}', '{');
    for (char c : s.toCharArray()) {
        if (pair.containsValue(c)) st.push(c);
        else if (st.isEmpty() || st.pop() != pair.get(c)) return false;
    }
    return st.isEmpty();
}

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

Question 10: 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 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 ISRO written examination

1. Technical Section is Critical: Must perform well in space 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: ISRO written examination
6. Focus Areas: Space technology, satellite communication, recent missions, engineering fundamentals
7. Enhanced Emphasis: Optimal solutions and recent missions knowledge

ISRO 2025 interview experiences

Based on recent candidate experiences from 2025 ISRO interviews:

2025 Interview Process:

1. Written Examination (90 minutes): Technical (40-50) + Aptitude (20-25)
2. Technical Interview (60-90 minutes): Space technology concepts, satellite communication, recent missions, engineering fundamentals, problem-solving
3. HR Interview (30-45 minutes): Behavioral questions, company fit, motivation, space technology passion

2025 Interview Trends:

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

Common 2025 Interview Topics:

• Technical: Space technology, satellite communication, recent missions, engineering fundamentals
• Aptitude: Quantitative reasoning, logical reasoning
• Behavioral: Problem-solving approach, space technology passion, teamwork, motivation

Success Tips:

• Strong technical performance is essential - master space technology and engineering fundamentals
• Understand satellite communication and recent ISRO missions
• Practice problem-solving in space technology domain
• Prepare behavioral examples demonstrating space technology passion
• Understand ISRO’s recent missions and space technology programs
• Practice explaining complex technical concepts clearly

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

Preparation tips for ISRO 2025 pattern

1. Master Technical Fundamentals: Focus on space technology, satellite communication, recent missions - study thoroughly
2. Engineering Fundamentals: Strong understanding of engineering fundamentals relevant to space technology
3. Practice Previous Year Papers: Solve ISRO 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 Missions: Deep understanding of ISRO’s recent missions and space technology innovations
7. Problem-Solving: Practice solving complex technical problems in space technology domain
8. Behavioral Preparation: Prepare examples using STAR format - space technology passion, problem-solving
9. Mock Tests: Take timed practice tests to improve speed and accuracy
10. ISRO Missions: Stay updated with ISRO’s recent missions and space technology programs

Comments & Suggestions

Related resources

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ISRO Technical Questions→

Interview experience→

Preparation guide→

ISRO hub→

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