Question

Which term of the sequence 4, 9 , 14, 19, ...... is 124 ?

Answer 1

Clearly, the given sequence is an A.P. with first term a = 4 and common difference d = 5.

Let 124 be the $n^{th}$ term of the given sequence. Then, $a_n$ = 124

$\Rightarrow a+(n–1)d=124$

$\Rightarrow 4+(n–1)\times 5=124$

$\Rightarrow n=25$

Hence, ${25}^{th}$ term of the given sequence is 124.