Question

The sum of first q terms of an AP is (63q - 3q²). If its pth term is -60, find the value of p. Also, find the 11^th term of its AP.

Answer 1

Let S_q denote the sum of the first q terms of the AP. Then,

\(\Rightarrow\) -6p + -60-66 = -126

\(\Rightarrow\) p = 21

Thus, the value of p is 21

putting q = 11 in (1), we get 

a₁₁ = -6 x 11 + 66 = -66 + 66 = 0

Hence, the 11th term of the AP is 0.