Question

The first term of an A.P is 6 and the common difference 3. Find S27.​

Answer 1

Given:

First Term (a) = 6

Difference (d) = 3

Solution:

$S(n) = 2a + (n - 1)d$

$S(27) = 2(6) + (27 - 1) 3 \\ S(27) = 12 + 26 \times 3 \: \: \: \: \: \: \: \: \: \: \\ S(27) = 12 + 78 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ S(27) = 90 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \:$

Answer. S(27) = 90