P= Rs. 6000, A= Rs. 6660 and the time period is 1 year. Find the interest and the rate of interest per annum.

A sum of Rs. 5120 amounts to Rs. 7290 in 3 years at compound interest. Find the rate of interest per annum.

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.

A sum of Rs. 16000 earns a simple interest of Rs. 2560 in 2 years. Find the rate of interest per annum.

If the interest on Rs. 800 be more than the interest on Rs. 400 by Rs. 40 in 2 years, then find the rate of interest per annum.

A sum of Rs 4200 becomes Rs 5082 in 3 years rate simple interest. What is the rate of interest per annum?

A sum amounts to Rs. 5600 in 4 years and Rs. 6400 in 6 years at a certain rate of simple interest. Find the rate of interest per annum and the sum.

Rs 775, invested for 8 years an interest of Rs 434. The rate of simple interest per annum is :