What will be the ratio of the interests earned by identical sum of money invested at the same rate of simple interest for 6 years and for 15 years respectively?

A certain sum amounts to ₹15,500 in 2 years at 12% p.a. simple interest. The same sum will amount to what in years at 10% p.a., if the interest is compounded half yearly (nearest to ₹1)?

A sum of money amounts to 5,200 in 5 years and to 5,680 in 7 years at simple interest. The rate of interest per annum is-

There is 80% increase in an amount in 8 years at simple interest. What will be the compound interest on Rs. 15,000 after 3 years at the same rate of interest?

Atm of ₹2.400. amounts to ₹3,264 in 4 years at a certain rate of simple interest. If the rate of interest is increased by 1% the same sum in the same time would amount to-

If , then the value of a+b is equal to:

In what time will ₹8000, at 3% per annum, produce the same interest as ₹6000 does in 5 years at 4% simple interest is? 

The simple interest on ₹ 7,300 from 11 May, 1987 to 10 September, 1987 (both days included) at 5% per annum is-