SOLUTION: A farmer needs 65 gallons of weed killer solution. He has 35% weed killer solution which is too weak for the job and a 60% weed killer solution which is too strong. How many gallon

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Question 172661: A farmer needs 65 gallons of weed killer solution. He has 35% weed killer solution which is too weak for the job and a 60% weed killer solution which is too strong. How many gallons of each solution should he mix to obtain 70 gallons of a 50% solution?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A farmer needs 65 gallons of weed killer solution.
He has 35% weed killer solution which is too weak for the job and a 60% weed killer solution which is too strong.
How many gallons of each solution should he mix to obtain 70 gallons of a 50% solution?
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active + active = active ingrediant
0.35x + 0.60(70-x) = 0.50*70
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35x + 60*70 - 60x = 50*70
-25x = -10*70
x = 28 (amt. of 35% killer needed in the mixture)
70-x = 42 ( amt. of 60% killer needed in the mixture)
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Cheers,
Stan H.