SOLUTION: Julie has $80,000 to invest. She invests part at 5%, one fourth this amount at 6%, and the balance 7%. Her total income from interest is $4,700. Find the amount invested at each ra

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Julie has $80,000 to invest. She invests part at 5%, one fourth this amount at 6%, and the balance 7%. Her total income from interest is $4,700. Find the amount invested at each ra      Log On


   

Question 1118536: Julie has $80,000 to invest. She invests part at 5%, one fourth this amount at 6%, and the balance 7%. Her total income from interest is $4,700. Find the amount invested at each rate
Answer by ikleyn(52798) About Me  (Show Source):
You can put this solution on YOUR website!
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This problem, although seems to be complicated from the first glance, is actually very simple one unknown problem.


Let x be the amount invested at 5%.


Then you have this "total interest" equation


0.05x + 0.06*(0.25x) + 0.07*(80000 - x - 0.25x) = 4700.


This equations tells everything about itself, you only need to hear it . . . I mean "to read it" . . . 


Please recognize that 0.25x is %281%2F4%29%2Ax.


Your job now is to simplify and solve it for x.