Question 471712:  I have worked on this problem for three days, and need some help please.
 
 The question ask: An investment of $57,000 was made by a business club. The investment was split into three parts and lasted for a year.The first part of the investment earned 8% interest, the second 6%, and the third 9% interest. Total interest from the investments was $4290. The interest from the first investment was three times the interest from the second. Find the amounts of the three part investments.
 
Investment 1 = 
Investment 2 = 
Investment 3 = 
 
Thanks so much, hopefully you can help! 
 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! An investment of $57,000 was made by a business club. The investment was split into three parts and lasted for a year.The first part of the investment earned 8% interest, the second 6%, and the third 9% interest. Total interest from the investments was $4290. The interest from the first investment was three times the interest from the second. Find the amounts of the three part investments.  
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3 equations with 3 variables: 
Quantity: x + y + z = 57000 
Interest:0.08x+0.06y+0.09z = 4290 
Interest:0.08x - 3*0.06y = 0 
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Rearrange: 
x    +   y  +   z    = 57000 
8x   +  6y  +  9z    = 429000 
8x   - 18y  +   0    = 0 
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Solve the system by any method you know to get: 
x = $36000 
y = $16000 
z = $5000 
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Cheers, 
Stan H. 
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