A man starts repaying a loan as first instalment of Rs 100 = 00.

Let $a_{30}$ be the amount a man repays in the 30 th instalment.

Let d be the common increment in his instalment every month.

Let a be the initial repayment.

Here, a = 100, d = 5, n = 30

Amount to be repaid in the 30th instalment:

$a_{30} \Rightarrow a+(n-1) d$

$=100+29 \times 5$

$=245$

Hence, the man repays Rs 245 in his 30th instalment.