Problema Solution
You invested $3000 between two accounts paying 3% and 9% annual interest, respectively. If the total interest earned for the year was $150, how much was invested at each rate?
Answer provided by our tutors
let
x = the money invested at 3% annual interest
y = the money invested at 9% annual interest
you invested $3000
x + y = 3000
the 3% interest earned from x + 9% interest earned from y = the total interest earned for the year
0.03x + 0.09y = 150
by solving the system of equations
x + y = 3000
0.03x + 0.09y = 150
we find
x = $2000
y = $1000
$2000 were invested at 3% annual interest.
$1000 were invested at 9% annual interest.