A mother wants to invest 8,000 dollars into her child's college fund. She invests a portion of the money into a CD account which earns 4% interest, and the remainder into a savings bond which earns 7% interest. If the total interest earned after one year is $480.00, how much money was invested in the CD account?

Answer 1

amount into lower rate account --- x
amount into higher rate account --- 8000-x

.04x + .07(8000-x) = 480
4x + 7(8000-x) = 48000
4x + 56000 - 7x = 48000
-3x = -8000
x = 8000/3 = 2666.67

amount into CD = $2666.67