Problema Solution
Efren has 88,000 and invested a portion of it at 9% simple interest and the remainder at 10% simple interest. If at the end of the year, the total interest from these two investments amounted to 8,470, how much did he invest at 10%?
Answer provided by our tutors
let
x = the money invested at 9% simple interest
y = the money invested at 10% simple interest
x + y = 88,000
at the end of the year, the total interest from these two investments amounted to 8,470
9% of x + 10% of y = 8470
0.09*x + 0.10*y = 8470
by solving the system of equations
x + y = 88000
0.09*x + 0.10*y = 8470
we find
x = $33,000
y = $55,000
he invested $55,000 at 10%.