joanna invested $7500, part at a 5.5% and the remainder at a 6% annual rate of interest. if she collected a total of 435 in interest at the end of one year, how much money was invested at each rate?

Answer 1

If x at 5.5%, the rest (7500-x) is at 6%. So, add up the interest:

.055x + .06(7500x) = 435