A woman has a total of $9000 to invest. She invests part of the money in an account that pays 7% per year and the rest in an account that pays 8% per year. If the interest earned in the first year is $664, how much did she invest in each account?

Answer 1

Let x = the amount invested in the 7% account

Let (9000 - x) = the amount invested in the 8% account

0.07x + 0.08(9000 - x) = 664

0.07x + 720 - 0.08x = 664

0.15x = 664 - 720

x = -56

Since x cannot be negative, the woman invested $0 in the 7% account and $9000 in the 8% account.