Question

Find the sum of first 16 terms of the A.P. whose n^th term is given by a_n = 5n -3

Answer 1

N^th term

a_n = 5n - 3

a₁ = (5 x 1) - 3 = 2

a₂ = (5 x 2) -3 = 7

a₁₆ = (5 x 16) - 3 = 77

Common difference, d = 7 - 2 = 5