Let Mohan paid Rs. P every year ∴ Interest for 1 year = P × 1 × 4/100 = P × 4/100 ∴ Amount due in 1 year = P + 4P/100 = Rs. 104P/100 Similarly Amount due In 2 years = P + 8P/100 = Rs. 108P/100 Amount due in 3 years = P + 12P/100 = Rs. 112P/100 Now since the last payment of Rs. P will be paid with no interest ∴ Amount due in 4th year = Rs. P ∴ According to the question 104P/100 + 108P/100 + 112P/100 + P = 1696 P × (104 + 108 + 112 + 100)/100 = 1696 ∴ P = 1696 × 100/424 ∴ P = Rs. 400