SOLUTION: Walt made an extra $9000 last year from a part-time job. He invested part of the money at a 9% annual rate of interest, and the rest at an 8% annual rate of interest. At the end of

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Walt made an extra $9000 last year from a part-time job. He invested part of the money at a 9% annual rate of interest, and the rest at an 8% annual rate of interest. At the end of      Log On


   

Question 198242This question is from textbook
: Walt made an extra $9000 last year from a part-time job. He invested part of the money at a 9% annual rate of interest, and the rest at an 8% annual rate of interest. At the end of the year, he made a total of $770 in interest. How much was invested at 8%? This question is from textbook

Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
.08x+.09(9,000-x)=770
.08x+810-.09x=770
-.01x=770-810
.01x=-40
x=-40/-.01
x=$4,000 amount invested @ 8%.
9,000-4,000=5,000 amount invested @ 9%.
Proof:
.08*4,000+.09*5,000=770
320+450=770
770=770