Question

Morton invest part of his $1200 at an annual rate of 5% and part at an annual rate of 7.5%. his total return on the two investments was $81. how much was invested at 5%

Answer 1

$360 Let's assign the variable x for the amount invested at 5%. That means that (1200-x) will be the amount invested at 7.5%. So the equation becomes: 0.05x + 0.075(1200-x) = 81 0.05x + 90 - 0.075x = 81 -0.025x + 90 = 81 90 = 81 + 0.025x 9 = 0.025x 360 = x So $360 was invested at 5% and the remaining ($1200 - $360 = $840 was invested at 7.5%.