## Elementary Algebra

Let X represent the amount of money invested at 3% interest. After a year, he received 3% of the X amount invested as interest. He received 3% $\times$ X = 0.03X Also, he invested 750 more than X, or X + 750 at 5% interest. After a year, he received 5% of the X + 750 as interest. He received 5% $\times$ (X + 750) = 0.05X + 37.50 His total yearly interest was 157.50. So: 0.03X + 0.05X + 37.50 = 157.50 0.08X = 120 Divide both sides by 0.08 X = 1500 He invested 1500 dollars at 3% interest. He invested 750 more than X, or 1500 dollars, at 5% interest. So, he invested 2250 dollars at 5% interest.