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| Question 179529:  Walt made an extra $12,000 last year from a part time job.  He invested part of the money at 7% and the rest at 9%.  He made a total of $970 in interest. How much was invested at 7%?
 Answer by MissionPossible(18)
      (Show Source): 
You can put this solution on YOUR website! He invested part of the money at 7% and the rest at 9%. How much was invested at 7%?    ----->   X
 invested part of the money at 7% would made X*0.07
 invested part of the money at 9% would made (12,000 - X)*0.09
 He made a total of $970 --->  970  =  X*0.07 + (12,000 - X)*0.07
 970  =  X*0.07 + (12,000 - X)*0.09
 970  =  X*0.07 + 1080 - 0.09X
 0.09X-0.07X =   1080 - 970
 0.02X       =    110
 X       =    110/0.02
 =    5500
 How much was invested at 7%?  $5,500   Ans.
 
 
 
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