Question

Which term of the sequence $-1,3,7,11,....$ is $95$?

Answer 1

Clearly, the given sequence is an A.P. such that

$a=$First term $=-1$ and, $d=$ Common difference $=4$

Let $95$ be the $n^{th}$ term of the given A.P. Then,
$a_n=95$

$⟹a+(n-1)d=95$

$⟹-1+(n-1)\times 4=95$

$⟹-1+4n-4=95$

$⟹4n-5=95⟹n=25$
Thus, $95$ is ${25}^{th}$ term of the given sequence.