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 

In what time will the simple interest be $$ {2\over5} $$ of the principal at 8% per annum? 

The simple interest on a certain sum of the money at 4 % per annum for 4 years is Rs.80 more than the interest on the same sum for 3 years at 5 % per annum. Find the sum.

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

A certain sum (in Rs.) is invested at simple interest at x% p.a. for 5 years. Had it been invested at (x+5)% p.a, the simple interest would have been Rs.9,200 more than the earlier one. What is the sum?

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

A sum of ₹ 10,000 is lent partly at 8 % and remaining at 10% per annum. If the yearly interest on the average is 9.2 %, the two parts are 

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?