The average of a and b is 40 and the sum of b and c is What is the value of a-c?

The average of a and b is 40 and the sum of b and c is What is the value of a-c?

A 5

B 10

C 15

D 20

Solution

Correct Answer: Option B

(a + b)/2 = 40

or, (a + b) = 80 .............................................. (1)

and,

b + c = 70 .................................. (2)

(1) - (2), we get,

a + b - b - c = 80 - 70

or, a - c = 10