Question

Find the four consecutive terms in an A.P . whose sum is -54 and the sum of first and third term is -30.

Answer 1

Given

a+a+d+a+2d+a+3d= - 54

4a+6d= - 54

2a+3d = - 27----(i)

And a+a+2d= - 30

2a+2d= - 30-----(ii)

From eqn i and ii we get

d=3 and a=-18

Hence sequence will be ;

-18, - 15, - 12, -9