Enter and solve a system of equations to find the amount invested in each amount enter the interest rates in order as given in the problem.

Question

helene invested a total of $1,300 in two simple interest bank accounts. One account paid 6% annual interest; the other paid 7% annual interest. The total amount of interest she earned after one year was $85.

Answer 1

.07X + (1300-X).06 = 85

.01X = 85 -.06(1300) = 85- 78= 7

X = 7/.01 = $700 invested at 7%

1300-700= $600 invested at 8%

which makes no sense

7% x 700 = 49

8% x 600 = 48

total 91 not 85

85/1300 = about 6.5%

you can't invest in 7 and 8% and get an average return of 6.5%. You'd get between 7 and 8, not less than 7 average.