Question

Find the term $t_{15}$ of an A.P.:
$4,9,14,.....$

Answer 1

The given A.P. is $4,9,14,....$
We have,
$a=$ First term $=4$
$d=$ Common difference $=5$
We know that the $n^{th}$ term of an A.P. with first term $a$ and common difference $d$ is given by
$t_n=a+(n-1)d$
$t_{15}=a+(15-1)d$
$=4+\left(14\right)5$
$=4+70$
$t_{15}=74$

Hence, the term $t_{15}$ is $74$