Question

If 18 , x , y , -3 are in A.P then find x + y.

Answer 1

15

Explanation:

If this is an arithmetic progression, then there is a common difference.

-3-18 = -21

-21/3 = -7

18 - 7 = x

x = 11

11 - 7 = y

y = 4

4 - 7 = -3

x + y

11 + 4 = 15