SOLUTION: can someone help me please with this problem To set up a chemistry lab experiment, you need to make 400 mL of 15% nitric acid solution. You have 20% and 5% nitric acid solutio

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Question 772799: can someone help me please with this problem
To set up a chemistry lab experiment, you need to make 400 mL of 15% nitric acid solution. You have 20% and 5% nitric acid solutions available. How much of each will you use to make up the required solution?
a) mL of 20% solution (nearest integer):
b) mL of 5% solution (nearest integer):
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
To set up a chemistry lab experiment, you need to make 400 mL of 15% nitric acid solution. You have 20% and 5% nitric acid solutions available. How much of each will you use to make up the required solution?
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let x=amount of 5% solution to use
400-x=amount of 20% solution to use
..
5%x+20%(400-x)=15%*400
.05x+80-.20x=60
.15x=20
x=400/3
400-x=800/3
amount of 5% solution to use=400/3 ml
amount of 20% solution to use=800/3 ml