Question

Mr X borrowed interest free loan of Rs.12000 from Mr Y the Loan is to be repaid in 10 installments Mr X paid Rs. 800 as first installment and then increases each installment by equal amount over the preceding installment what will be the last installment​

Answer 1

Answer;

Last installment = Rs1600

Explanation:

Mr.X borrowed interest free loan from MrY (S)= Rs 12000

Total number of instalments (n) = 10

First installment = Rs800

and

Let the amount is increases each installment by equal amount over the preceding installment = Rs x

Now , 10 instalments are

800,800+x,800+2x,....,800+9x

$\boxed {S_{n} = \frac{n}{2}\left(a+a_{n}\right)}$

$\implies\frac{10}{2}\left(800+800+9x\right)=12000$

$\implies 5(1600+9x)=12000$

$\implies 1600+9x = 2400$

$\implies 9x = 2400-1600$

$\implies 9x = 800$

$\implies x = \frac{800}{9}$

Now ,

Last installment amount = 800+9x

= 800 + 9(800/9)

= 800+800

= 1600

Therefore,

Last installment amount = Rs1600

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