<PRE><B>Question 1134717</B>
Rachel has 25% acid solution and a 50% acid solution. How many liters of each solution should she mix if she wants to obtain 100 liters of a 40% acid solution? 
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t = 25%
f = 50%
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t + f = 100 ---- total solution
25t + 50f = 100*40  ------- total acid
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Solve them.
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