On a certain sum, the compound interest in 2 years amounts to ₹ 4240. If the rates of interest for successive years are 10% and 15% respectively, find the sum.

At what rate per cent compound interest, does a sum of money become 1.44 times of itself in 2 years ?

A person invests ₹ 5000 for three years at a certain rate of interest compounded annually. At the end of two years this sum amounts to ₹ 6272. Calculate :

(i) the rate of interest per annum.

(ii) the amount at the end of the third year.

In how many years will ₹ 7000 amount to ₹ 9317 at 10 per cent per annum compound interest ?