## Elementary Algebra

Let X represent the amount of money invested at 7%. We receive 7% $\times$ X = 0.07X from this investment. From the 3000 dollars invested at 4% we receive: 4% $\times$ 3000 = 120 The average return for both investments is 5%. The total for both investments equals 3000 + X, so we can set up the following equation: 0.07X + 120 = .05 $\times$ (3000 + X) 0.07X + 120 = 150 + 0.05X 0.02X = 30 Divide both sides by 0.02: X = 1500 1500 dollars must be invested at 7%.