SOLUTION: Hector is performing a chemistry experiment that requires 140 mL of a 30% copper sulfate solution. he has a 25% copper sulfate solution and a 60% copper sulfate solution. How many

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Question 911425: Hector is performing a chemistry experiment that requires 140 mL of a 30% copper sulfate solution. he has a 25% copper sulfate solution and a 60% copper sulfate solution. How many milliliters of each solution Gould he mix to obtain the needed solution?
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
We need a total of 140 mL at 30%
We want to know how many mL at 25% to mix with 60%
a+b=140,
0.25*a+0.6*b=0.3*140
a=140-b
0.25*(140-b)+0.6*b=42
35-0.25b+0.6*b=42
0.35*b=7
b=20
a=140-b
a=120 mL at 25%
b=20 mL at 60%
check
0.25*120+0.6*20=0.3*140
30+12=42
42=42
ok
codemx1