Quantitative Aptitude — MCQ Practice Questions & Answers

Question 1

The average age of 5 friends is 24 years. If one friend leaves the group, the average age becomes 22 years. What is the age of the friend who left?

Accepted Answer

Correct answer: A. 32 years — Sum of 5 friends = 5 × 24 = 120. Sum of 4 friends = 4 × 22 = 88. Age of friend who left = 120 - 88 = 32 years.

Answer

B. 34 years

Answer

C. 36 years

Answer

D. 30 years

Question 2

A shopkeeper bought 10 items at ₹50 each and 15 items at ₹40 each. What is the average cost per item?

Accepted Answer

Correct answer: A. ₹44 — Total cost = (10 × 50) + (15 × 40) = 500 + 600 = 1100. Total items = 25. Average = 1100/25 = ₹44.

Answer

B. ₹43

Answer

C. ₹45

Answer

D. ₹46

Question 3

The average of 6 numbers is 18. If 3 more numbers with an average of 24 are added, what is the new average?

Accepted Answer

Correct answer: A. 20 — Sum of 6 numbers = 6 × 18 = 108. Sum of 3 numbers = 3 × 24 = 72. Total sum = 180. Total numbers = 9. New average = 180/9 = 20.

Answer

B. 21

Answer

C. 22

Answer

D. 19

Question 4

A train travels 120 km in 2 hours and then 180 km in 3 hours. What is the average speed of the train?

Accepted Answer

Correct answer: A. 60 km/h — Total distance = 120 + 180 = 300 km. Total time = 2 + 3 = 5 hours. Average speed = 300/5 = 60 km/h.

Answer

B. 65 km/h

Answer

C. 62 km/h

Answer

D. 58 km/h

Question 5

A student scored 75, 82, and 88 in three subjects. What score is needed in the fourth subject to get an average of 85?

Accepted Answer

Correct answer: A. 95 — Sum needed for average 85 in 4 subjects = 4 × 85 = 340. Sum of 3 scores = 75 + 82 + 88 = 245. Fourth subject score = 340 - 245 = 95.

Answer

B. 93

Answer

C. 92

Answer

D. 94

Question 6

The average weight of A, B, and C is 70 kg. If A's weight is 75 kg and B's weight is 68 kg, what is C's weight?

Accepted Answer

Correct answer: C. 67 kg — To find C's weight, use the definition of average: the sum of all values divided by the count equals the average. **Step 1: Set up the average formula** The average weight of A, B, and C is 70 kg, so: 	ext{Average} = \frac{	ext{A's weight} + 	ext{B's weight} + 	ext{C's weight}}{3} = 70 **Step 2: Express the sum of weights** Multiply both sides by 3 to find the total weight: 	ext{A's weight} + 	ext{B's weight} + 	ext{C's weight} = 70 	imes 3 = 210\,	ext{kg} **Step 3: Substitute known values** We know A = 75 kg and B = 68 kg. Substitute into the equation: 75 + 68 + 	ext{C's weight} = 210 **Step 4: Solve for C's weight** 143 + 	ext{C's weight} = 210 	ext{C's weight} = 210 - 143 = 67\,	ext{kg} **Answer: C's weight is 67\,	ext{kg} (Option C)**

Answer

A. 69 kg

Answer

B. 71 kg

Answer

D. 73 kg

Question 7

The average score of 5 students in Mathematics is 78. If one student who scored 68 leaves and a new student joins with score 88, what is the new average?

Accepted Answer

Correct answer: B. 82 — **To find the new average, we must first calculate the total score change when a student leaves and a new student joins.** **Step 1: Find the Total Score of Original 5 Students** The average of 5 students is 78, so we multiply the average by the number of students to get the total. 	ext{Total Score} = 	ext{Average} 	imes 	ext{Number of Students} = 78 	imes 5 = 390 **Step 2: Calculate the New Total Score** When a student scoring 68 leaves, we subtract 68. When a new student scoring 88 joins, we add 88. 	ext{New Total} = 390 - 68 + 88 = 410 **Step 3: Find the New Average** The number of students remains 5. Divide the new total by 5 to get the new average. 	ext{New Average} = \frac{	ext{New Total}}{	ext{Number of Students}} = \frac{410}{5} = 82 **The new average is 82.** **Answer: (B) 82**

Answer

A. 80

Answer

C. 81

Answer

D. 79

Question 8

The average of 4 numbers is 35. If three numbers are 28, 36, and 42, what is the fourth number?

Accepted Answer

Correct answer: A. 34 — Sum of 4 numbers = 35 × 4 = 140. Sum of 3 numbers = 28 + 36 + 42 = 106. Fourth number = 140 - 106 = 34.

Answer

B. 36

Answer

C. 38

Answer

D. 40

Quantitative Aptitude - MCQ Practice Questions