A washing machine was purchased under installment system, cash down payment is ₹ 3,000 and 3 equal annual installments of ₹1,300 are payable at the end of first, second and third year. If rate of interest is 10% p.a. under simple interest. Find the price of washing machine and the total interest charged under installment plan.

Let the price of washing machine = Rs. $$100x$$

Rate of interest is 10% for 3 years under simple interest

=> S.I. = $$\frac{P\times R\times T}{100}$$

Total amount paid = $$3000+(3\times1300)=Rs.$$ $$6900$$

=> $$100x+\frac{(100x-3000)\times10\times3}{100}=6900$$

=> $$100x+(x-30)\times30=6900$$

=> $$130x-900=6900$$

=> $$130x=6900+900=7800$$

=> $$x=\frac{7800}{130}=60$$

$$\therefore$$ Sum = Rs. 6,000$$ and thus total interest charged = Rs. 900

=> Ans - (D)