[" A certain sum amounts to four times the princi- "],[" pal within a period of "2" years.The rate of simple "],[" interest per annum is "]

A certain sum amounts to four times the principal within a period of 2 years. The rate of simple interest per annum is

The amount of ₹ a in 20 years at the rate of simple interest of a % per annum is ………………

At r% per annum a sum become 2 times after 20 years. The rate of interest per annum is :

If the simple interest on a certain sum of money is 4//25th of the sum and the rate per cent equal to the number of years, then find the rate of interest per annum.

A certain sum of money will be doubled in 15 years at the rate of simple interest percent per annum of

With a given rate of simple interest, the ratio of principal and amount for a certain period of time is 4 : 5. After 3 years, with the same rate of interest, the ratio of the principal and amount becomes 5: 7. The rate of interest per annum is

A certain money amounts 9440Rs on simple interest in 3 years. If the rate of simple interest be 25% increased per annum, then the money will become 9800Rs after same period of time. Find the principal and the rate of interest in percent per annum.