SOLUTION: Angela needs 20qts of 50% antifreeze solution in her radiator. She plans to obtain this by mixing some pure antifreeze with an appropriate amount of a 40% antifreeze solution. How

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Question 134007: Angela needs 20qts of 50% antifreeze solution in her radiator. She plans to obtain this by mixing some pure antifreeze with an appropriate amount of a 40% antifreeze solution. How many quarts of each should she use?
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
X+.4(20-X)=.5*20
X+8-.4X=10
.6X=10-8
.6X=2
X=2/.6
X=3 1/3 OR 10/3 QTS OF PURE ANTIFREEZE IS NEEDED.
PROOF
10/3+.4(20-10/3)=10
10/3+.4[(60-10)/3]=10
10/3+.4(50/3)=10
10/3+20/3=10
30/3=10
10=10