Question 433417
A nurse has a solution that is 25% alcohol and another that is 50% alcohol. How much of the 25% alcohol must she use to make 20 L of a solution that is 40% alcohol?
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Two-variable solution:
Quantity Eq: t + f = 20 L
Alcohol Eq:0.25t+0.50f = 0.40*20
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Multiply thru Quantity by 50
Multiply thru Alcohol by 100
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50t + 50f = 50*20
25t + 50f = 40*20
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Subtract and solve for "t":
25t = 10*20
t = 8 L (amt. of 25% solution needed)
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Cheers,
Stan H.
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