At what rate of simple interest per annum in percent, the ratio of a principal and its amount will be `50 : 59` after `3` years?

At what rate of simple interest per annum in percent the interest of a principal in 20 years will be (4)/(9) part of its amount ?

At what rate of simple interest in percent per annum, the ratio of principal and its interest after 20 years is 1:1 ?

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 same rate of interest, the ratio of the principal and amount becomes 5 : 7. The rate of interest is____

Find the rate of simple interest in percent per annum if the simple interest of a principal is 3/5 part of the amount in 10 years.

At a rate of simple interest 7(1)/(2)% per annum, find the total amount of a principal of Rs600 in 219 days.

Find the rate of simple interest in percent per annum, if a principal becomes (4)/(9) part of its amount in a period of time of 20 years.

The simple interest of a principal in 1 year and 9 months at the rate of simple interest of 5% per annum is 63Rs more than of the same principal in 2 years and 4 months at the rate of simple interest of 4(1)/(2)% per annum. Find the principal.

At the same rate of simple interest in percent per annum, if a principal becomes the amount of 7100Rs in 7 years and of 6200Rs in 4 years. Determine the principal and rate of simple interest in percent per annum.

At the same rate of simple interest in percent per annum, if a principal becomes the amount of Rs 1248 in 7 years and or Rs 1056 in 4 years. Find the principal and rate of simple interest in percent per annum.

The total interest at the rate of simple interest of 5% per annum of Rs300 and at the rate of simple interest of 3% per annum of Rs500 for 2 years more period of time, is together Rs150 . Find the period of time for which the interest of two principals have been claculated.