total interest rec'd / initial investment = total return
let x = the weight of $ invested at rate "y" and (1 - x) = weight of $ invested at rate "z", then:
(x * rate y) + (1 - x)(rate z) = total return
solve for x and (1 - x) then multiply each of those by the original amount invested
example: given: $1,000 invested, y = 0.02 (2%) and z = 0.05 (5%), interest earned $32
32/1000 = 0.032
(x * rate y) + (1 - x)(rate z) = total return
0.02x + [(1 - x)(0.05)] = 0.032
0.02x + 0.05 - 0.05x = 0.032
-0.03x = -0.018
x = 0.60
so 1 - x = 0.40
$1,000x = $1,000(0.60) = $600
and
$1,000(1 - x) = $1,000(0.40) = $400
check math:
$600*0.02 = $12
$400 * 0.05 = $20
total interest: $32
impossible to answer with the information you provided
Last year, Christine had
to invest. She invested some of it in an account that paid
simple interest per year, and she invested the rest in an account that paid
simple interest per year. After one year, she received a total of
in interest. How much did she invest in each account?
