First term and common difference of an A.P. are 6 and 3 respectively ; find S₂₇.

a = 6, d = 3, S₂₇ = ?

Given: First term a = 6

Common Difference d = 3

To find: S₂₇ where n = 27

By using sum of n^th term of an A.P. is

Where, n = no. of terms

a = first term

d = common difference

S_n = sum of n terms

Thus, Substituting given value in formula we can find the value of S₂₇

Thus, S₂₇ = 1215