SOLUTION: Mr. Turner invested a sum of money at 7% and twice that sum at 3%. His yearly return was $390. How much did Mr. Turner invest at each rate? (This problem is not from a textbook).

Question 38951: Mr. Turner invested a sum of money at 7% and twice that sum at 3%. His yearly return was $390. How much did Mr. Turner invest at each rate?
(This problem is not from a textbook). Please help, Thank You
Answer by fractalier(6550) (Show Source): You can put this solution on YOUR website!
Let x be what he invested at 7%.
Thus 2x is what was invested at 3%.
So we have
(.07)x + (.03)(2x) = 390
multiply by 100 to clear decimals
7x + 6x = 39000
13x = 39000
x = $3000 at 7%
2x = $6000 at 3%
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