The average of 7 numbers is 60. The average of the first three numbers is 50, while the average of the last three is 70. What must be the remaining number ?

Answer : B. 60

The average of 7 numbers is 60. The average of the first three numbers is 50, while the average of the last three is 70. What must be the remaining number ?

A. 75

B. 60

C. 65

D. 55

Answer : B. 60

Explanation:

The sum of all the seven numbers = 60 * 7 = 420
The sum of the first three = 50 * 3 = 150
The sum of the last three = 70 * 3 = 210
Remaining Number = 420 – (210 + 150) = 60

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