A certain sum amounts to ₹13200 after 4 years and to

Solution

As we know in simple interest the interest is always constant if the rate and sum are same So, Interest for 4 years = 16400 - 13200 ⇒ Rs. 3200 So, for the 1st 4 years, the interest will be Rs. 3200   [As mentioned earlier interest will be the same] So, sum = 13200 - 3200 ⇒ Rs. 10000 Now, S.I = (10000 × 10 × 16)/(100 × 5) ⇒ 100 × 2 × 16 ⇒ Rs. 3200 ∴ The simple interest (in Rs.) on the same sum at 10% p.a. for 3(1/5) years will be 3200.