Question 1023988
A lab needs to make 100 gallons of an 18% acid solution by mixing a 12% acid 
solution with a 20% solution. How many gallons of each solution are needed? 
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Quantity:: t + w = 100 gallons
Acid Eq:: 0.12t + 0.20w = 0.18*100
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Modify for elimination::
12t + 12w = 12*100
12t + 20w = 18*100
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Subtract and solve for "w"::
8w = 6*100
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w = 75 gallons (amt. of 20% solution needed)
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Solve for "t"::
t = 100 - 75 = 25 gallons (amt. of 12% solution needed)
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Cheers,
Stan H.
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