Q47 of 176 Page 8

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?

The 1st installment of the loan = Rs. 100


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


The 3rd 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 30th installments is Rs. 5175


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