Question

Mary had $25,000 to invest. She invested part of that amount at 3% annual interest and part at 5% annual interest for one year. The amount of interest she earned for both investments was $1100. How much was invested at each rate?

Answer 1

(25000-f)(.03)+.05f=1100

750-.03f+.05f=1100

750+.02f=1100

.02f=350

f=$17500

So Mary invested $17500 @ 5% and 7500 at 3% to earn $1100 in interest.