SOLUTION: Walt made an extra $9000 last year from a part-time job. He invested part of the money at 9% and the rest at 8%. He made a total of $780 in interest. How much was invested at 8%

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: Walt made an extra $9000 last year from a part-time job. He invested part of the money at 9% and the rest at 8%. He made a total of $780 in interest. How much was invested at 8%      Log On


   

Question 116688: Walt made an extra $9000 last year from a part-time job. He invested part of the money at 9% and the rest at 8%. He made a total of $780 in interest. How much was invested at 8%?
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
.09X+.08(9000-X)=780
.09X+720-.08X=780
.01X=780-720
.01X=60
X=60/.01
X=$6,000 INVESTED @ 9%
9,000-6,000=3,000 INVESTED @ 8%
PROOF:
.09*6,000+.08*3,000=780
540+240=780
780=780