Question

In an AP, the sum of first n terms is $\frac{3n^2}{2}+\frac{13n}{2}$ Find the 25th term.

Answer 1

Given,

$S_n=\frac{3n^2}{2}+\frac{13n}{2}$

$T_{25}=S_{25}-S_{24}$

$=\frac{3(25{)}^2}{2}+\frac{13\left(25\right)}{2}-\frac{3(24{)}^2}{2}-\frac{13\left(24\right)}{2}$

$=1100-1020$

$=80$

Hence, this is the answer.