The Two Bank CDs

13)  With $15,000, George bought two CDs from two different banks.
One would pay 3% annual interest, while the other would pay 5%.
If his total interest earnings for the year were $650 from these
two CDs, then how much had he invested in each one?

"x" = will be the value of  the 3% CD

Therefore, "15,000-x" will be the value of the 5% CD.

        0.03(x) + 0.05(15,000 - x) = 650.00

Move decimal points two to the right:

        3(x) + 5(15,000 -x) = 65,000

        3x + 75,000 -5x = 65,000

        3x -5x =  -10,000

        -2x = -10,000

        x = 5,000  (a negative divided by a negative results 
                   in a positive)

        So George invested the following:

                $5,000 (x) in the 3% CD
               $10,000 (15,000-x) in the 5% CD