lets say that the first part of 59,000 (that was at an interest rate of 15% per year) is "x"
lets say that the second part of 59,000 (interest rate of 4% per year) is "59000 - x"
what we are trying to find is the value of "x"
assuming that one year has passed:
15%*x + 4%*(59000-x) = $5440
expand 4%*(59000-x) = 4%*59000 - 4%*x
15%*x + 4%*59000 - 4%*x = $5440
15%*x + 2360 - 4%*x = $5440
15%*x - 4%*x = $3080
11%*x = $3080
(11/100)*x = $3080
x = (3080/11)*100
x = 28000
therefore the amount that was loan out with an interest of 15% per year is $28000 assuming that the interest received was from one year
