Problema Solution
A total of $4000 was invested, part of it at 8% interest and the remainder at 9%. If the total yearly interest amounted to $7290,how much was invested at each amount
Answer provided by our tutors
let
x = the amount invested at 8% interest, x>0
y = the amount invested at 9% interest, y>0
A total of $4000 was invested:
x + y = 4000
the total yearly interest amounted to $7290:
0.08x + 0.09y = 7290
by solving the system of equations:
x + y = 4000
0.08x + 0.09y = 7290
we find negative solution for x but that is impossible (x must be positive) thus this problem has no solution or it is impossible to invest $4,000: part of it at 8% interest and the remainder at 9% and have total yearly interest amounted to $7290.
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