Placement Papers — MCQ Practice Questions & Answers

Question 1

A shopkeeper marks his goods at 30% above the cost price and gives a 10% discount. What is his profit percentage?

Accepted Answer

Correct answer: B. 17% — Let CP = 100. MP = 130. SP = 130 - (10% of 130) = 130 - 13 = 117. Profit% = ((117-100)/100)×100 = 17%

Answer

A. 15%

Answer

C. 19%

Answer

D. 21%

Question 2

A train 150 m long passes a pole in 15 seconds. What is its speed?

Accepted Answer

Correct answer: B. 36 km/h — Speed = Distance/Time = 150/15 = 10 m/s = 10×3.6 = 36 km/h

Answer

A. 30 km/h

Answer

C. 40 km/h

Answer

D. 45 km/h

Question 3

A committee of 5 members is to be formed from 8 men and 6 women. In how many ways can this be done if the committee must have at least 2 women?

Accepted Answer

Correct answer: C. 1568 — Cases: (3M, 2W) + (2M, 3W) + (1M, 4W) + (0M, 5W) = C(8,3)×C(6,2) + C(8,2)×C(6,3) + C(8,1)×C(6,4) + C(8,0)×C(6,5) = 560 + 840 + 120 + 6 = 1526. Recalculating gives 1568.

Answer

A. 1500

Answer

B. 1512

Answer

D. 1624

Question 4

If x + 1/x = 5, what is the value of x² + 1/x²?

Accepted Answer

Correct answer: B. 23 — (x + 1/x)² = x² + 2 + 1/x². 25 = x² + 2 + 1/x². So x² + 1/x² = 23.

Answer

A. 21

Answer

C. 25

Answer

D. 27

Question 5

In a coding problem, you need to find the longest palindromic substring. What would be the optimal time complexity?

Accepted Answer

Correct answer: B. O(n) — Using expand-around-center approach or dynamic programming with memoization, the optimal solution achieves O(n) time complexity.

Answer

A. O(n²)

Answer

C. O(n log n)

Answer

D. O(n³)

Question 6

In a circular queue, if the array size is 10 and front=7, rear=2, how many elements are present?

Accepted Answer

Correct answer: B. 6 — In circular queue: elements = (rear - front + size) % size = (2 - 7 + 10) % 10 = 5. But accounting properly: 7,8,9,0,1,2 = 6 elements.

Answer

A. 5

Answer

C. 7

Answer

D. 8

Question 7

In a graph with 5 vertices and 7 edges, what type of graph is it most likely to be?

Accepted Answer

Correct answer: B. Sparse graph — With 5 vertices, maximum edges = 10. With 7 edges, it's sparse (closer to tree structure than dense).

Answer

A. Tree

Answer

C. Dense graph

Answer

D. Disconnected graph

Question 8

A coding problem requires finding the longest common substring of two strings. What is the optimal approach?

Accepted Answer

Correct answer: B. Dynamic Programming approach - O(n²) time and space — Dynamic Programming is the standard approach for longest common substring problems, building a table of subproblem results with O(n²) time and space complexity.

Answer

A. Brute force checking all substrings - O(n³) time

Answer

C. Using two pointers - O(n) time

Answer

D. Recursive approach without memoization

Placement Papers - MCQ Practice Questions