SOLUTION: Please help me. I keep getting stuck on this one: Jack's employer gave him a bonus of $1600. He invested all of the money, some at 5%, some at 7%, and some at 8%. He invested

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Please help me. I keep getting stuck on this one: Jack's employer gave him a bonus of $1600. He invested all of the money, some at 5%, some at 7%, and some at 8%. He invested      Log On


   

Question 528328: Please help me. I keep getting stuck on this one:
Jack's employer gave him a bonus of $1600. He invested all of the money, some at 5%, some at 7%, and some at 8%. He invested three times more money at 8% than he did at 5%. At the end of 1 year, the total earned interest was $115.
What kind of mathematical model could be used to solve this problem and why?
Solve the problem.
Why couldn't you solve the problem is you didn't know that Jack invested three times more money at 8% than at 5%?
Thanks for your help.
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
(5%)(x) + (8%)(3x) + (7%)(1600 - 4x) = 115