In what time will the annual simple interest rate at $$ {6{1\over4}{\%}}$$ , 72 rupees becomes 81 rupees?

A sum of money at simple interest amount to Rs.4800 in 3 years and Rs.5600 in the 5 years. The sum is

The simple interest and the true discount on a certain sum for a given period and at a given rate are 25 and 20 respectively. The sum is 

If the simple interest on ₹ 1 for 1 month is 1 paisa, then the rate percent per annum will be 

A sum of money at double the rate of simple interest doubles itself in 10 years. In how much time will that amount be triple of itself?

The difference between the compound interest and simple interest of a certain sum of amount is rupees 256.40 for 4 years at 10% rate per annum. Find the sum of money?

Alipta got some amount of money from her father. In how many years will the ratio of the money and the interest obtained from it be 10:3 at the rate of 6% simple interest per annum?

Which amount will be Rs 520 in 5 years with simple interest and Rs 568 in 7 years?