A man starts repaying a loan as first instalment of Rs. 100. If he increases the instalment by Rs 5 every month, what amount he will pay in the 30^th instalment?

First instalment = Rs 100

Instalment increases by Rs 5

Second Instalment = Rs 105

So, every month instalment Increases by 5

Man repays 100, 105, 110, ………… every month

This forms an A.P.

A.P. is 100, 105, 110, 105, …….

First term of A.P. = 100

Common difference = 5

n^th term of A.P. = t_n = a + (n – 1)d

30^th term = t₃₀ = 100 + (30 – 1) × 5

= 100 + 29 × 5 = 100 + 145

t₃₀ = 245

Man will pay Rs 245 in 30^th instalment.