Question

Find the common difference of an A.P. whose first term is 5 and the sum of its first four terms is half the sum of the next four terms.

Answer 1

Correct Answer - 2
`{5+(5+d) + (5+2d) + (5+3d)} = (1)/(2) {(5+4d) + (5+5d) + (5+6d) + (5+7d)}`
`rArr 2(20 +6d) = (20 +22d) rArr 10d = 20 rArr d = 2.`