Two equal amount of money are deposited in two banks, each at .............. their interest is Rs 288, what is each sum?

Question

Two equal amount of money are deposited in two banks, each at 15% per annum, for 7/2 years and 5 years.
If the difference between their interest is Rs 288, what is each sum?

Answer 1

Let the sum be x.
(x*5*15)/100-x*15*7/2*1/100=288
x=1280