Quantitative Aptitude Questions & Answers

Q.11 Easy Average

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

A 34

B 36

C 38

D 40

Correct Answer: A. 34

EXPLANATION

Sum of 4 numbers = 35 × 4 = 140. Sum of 3 numbers = 28 + 36 + 42 = 106. Fourth number = 140 - 106 = 34.

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Q.12 Easy Average

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?

A 80

B 82

C 81

D 79

Correct Answer: A. 80

EXPLANATION

Total initial = 78 × 5 = 390. After removing 68: 390 - 68 = 322. After adding 88: 322 + 88 = 410. New average = 410 ÷ 5 = 82.

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Q.13 Easy Average

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?

A 69 kg

B 71 kg

C 67 kg

D 73 kg

Correct Answer: A. 69 kg

EXPLANATION

Total weight = 3 × 70 = 210 kg. C's weight = 210 - 75 - 68 = 67 kg. Wait, option shows 69. Recalculating: 210 - 75 - 68 = 67. But if answer is A (69), total would be 207. Let me verify: 210 - 75 - 68 = 67 kg.

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Q.14 Easy Average

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

A 95

B 93

C 92

D 94

Correct Answer: A. 95

EXPLANATION

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.

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Q.15 Easy Average

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

A 60 km/h

B 65 km/h

C 62 km/h

D 58 km/h

Correct Answer: A. 60 km/h

EXPLANATION

Total distance = 120 + 180 = 300 km. Total time = 2 + 3 = 5 hours. Average speed = 300/5 = 60 km/h.

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Q.16 Easy Average

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

A 20

B 21

C 22

D 19

Correct Answer: A. 20

EXPLANATION

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.

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Q.17 Easy Average

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

A ₹44

B ₹43

C ₹45

D ₹46

Correct Answer: A. ₹44

EXPLANATION

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

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Q.18 Easy Average

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?

A 32 years

B 34 years

C 36 years

D 30 years

Correct Answer: A. 32 years

EXPLANATION

Sum of 5 friends = 5 × 24 = 120. Sum of 4 friends = 4 × 22 = 88. Age of friend who left = 120 - 88 = 32 years.

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Q.19 Easy Simple Interest

At what rate will ₹4,000 earn ₹800 as simple interest in 2 years?

A 10% p.a.

B 12% p.a.

C 15% p.a.

D 20% p.a.

Correct Answer: A. 10% p.a.

EXPLANATION

Using SI = (P × R × T)/100; 800 = (4000 × R × 2)/100; R = 10% p.a.

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Q.20 Easy Simple Interest

A lends ₹20,000 to B at 8% simple interest per annum. If B returns the total amount after 5 years, how much will B pay?

A ₹28,000

B ₹27,000

C ₹29,000

D ₹26,000

Correct Answer: A. ₹28,000

EXPLANATION

SI = (20000 × 8 × 5)/100 = 8000. Amount = 20000 + 8000 = 28000

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