The average of 12 numbers is 40. Later average becomes 42 when two numbers are changed. The difference in sum? MCQ with Answer and Explanation

The average of 12 numbers is 40. Later average becomes 42 when two numbers are changed. The difference in sum?

A. 20

B. 24

C. 30

D. 28

Answer: Option B

Increase in average 2, for 12 =24 increase in sum.

This question belongs to: Maths Average

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Question #1 Report Error

If the average of 7 numbers is 35 and the average of first 4 is 32, average of last 4 is 38. What is the 4th number?

A. 32

B. 28

C. 35

D. 30

Correct Answer: Option C

Explanation:
Sum of 7 = 7×35=245. Sum first 4=4×32=128. Sum last 4=4×38=152. 4th number = 128 + 152 - 245 = 35.

This question belongs to: Maths Average

Question #2 Report Error

The average of 8 numbers is 50. If one number 70 is replaced by 54, what is the new average?

A. 50

B. 48

C. 49

D. 52

Correct Answer: Option B

Explanation:
Original total = 8×50 = 400. New total = 400−70+54 = 384. New average = 384/8 = 48.

This question belongs to: Maths Average

Question #3 Report Error

The average of 4 numbers is 12. If each number is multiplied by 2 and then 5 is added, what is the new average?

A. 24

B. 27

C. 29

D. 30

Correct Answer: Option C

Explanation:
New average = (12×2)+5 =24+5=29.

This question belongs to: Maths Average