If the compound interest in the third year at 8% p.a. on certain sum is ₹3600, then what is the difference between the compound interest in the 4th and 5th year? (nearest to an integer in ₹)

₹311

Compound interest on a certain sum in 3rd year is = Rs. 3600

Rate of Interest = 8%

Compound interest on a certain sum in 4th year is = 3600 +  3600 × \(\frac{8}{100}\)

= 3600 +  3600 × \(\frac{2}{25}\)

= 3600 + 288

= 3888

Compound interest on a certain sum in 5th year is = 3888 +  3888 × \(\frac{8}{100}\)

= 3888 +  3888 × \(\frac{8}{100}\)

= 3888 +  3888 × \(\frac{2}{25}\)

= 3888 + 311.04

= 4199.04

So, Required difference b/w compound interest of a certain sum of 4th and 5th year

= 4199.04 - 3888

= 311.04

= 311    ( nearest integer )