If 64 amount to 83.20 in 2 years what will ₹ 86 amount to in 4 years at the same rate percent per annum? 

The simple interest on a sum  of money is $$8\over 25$$ of the sum. If the number of years is numerically half the rate percent per annum, then the rate percent per annum is 

At some rate of simple interest, A lent ₹ 6,000 to B for 2 years and ₹ 1,500 to C for 4 years and received ₹ 9,00 as interest from both of them together. The rate of interest per annum was

At what rate per cent per annum will a sum of money double in 8 years?

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-

In 5 years, the simple interest on an amount of Rs. X is $$2\over 5$$ of the principal. The rate of interest per annum is:

A sum of money becomes Rs 16000 in 6 years at the rate of 25% per annum simple interest. What is the total interest for 6 years?

Mahesh invests a sum of money which becomes Rs. 1344 in 3 years and Rs. 1536 in 7 years. How much had he invested?