Question

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

Answer 1

The 1^st installment of the loan = Rs. 100

the 2^nd installment of the loan = Rs 100 + 5 = Rs 105

The 3^rd installment of the loan = Rs 105 + 5 = Rs 110

Therefore, the AP is 100, 105, 110, …

Here, a = 100, d = 105 – 100 = 5 and n = 30

We know that,

⇒ S₃₀ = 15 [200 + 29 × 5]

⇒ S₃₀ = 15 [200+145]

⇒ S₃₀ = 15 [345]

⇒ S₃₀ = 5175

Hence, the amount he will pay in 30^th installments is Rs. 5175