Question

Find four consecutive term in


a.p whose sum is 12 qn

Answer 1

Let the four consecutive terms in an A.P. be a – 3d, a – d, a + d, a + 3d


As per the first condition,


a – 3d + a – d + a + d + a + 3d = 12


∴  4a = 12


∴ a = 12/4


∴ a = 3 ...........eq. (i)


As per the second condition,


a + d + a + 3d = 14


∴ 2a + 4d = 14



∴ 2 (3) + 4d = 14 [From eq. (i)]


∴ 6 + 4d = 14


∴ 4d = 14 – 6


∴ 4d = 8


∴ d = 8/4


∴ d = 2


∴ a – 3d = 3 – 3 (2) = 3 – 6 = – 3


a – d = 3 – 2 = 1


a + d = 3 + 2 = 5


a + 3d = 3 + 3 (2) = 9

∴ The four consecutive terms of A.P. are – 3, 1, 5 and 9