SOLUTION: A scientist needs 5L of 12% solution. She has on 10% and 17% solution. How much of each does she need?

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Question 350685: A scientist needs 5L of
12% solution. She has
on 10% and 17%
solution. How much of
each does she need?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let A be the amount of 10% solution and B the amount of 17%
solution.
Volume equation:
1.A%2BB=5
Concentration equation:
2.10A%2B17B=12%285%29=60
Multiply eq. 1 by -10 and add it to eq. 2,
-10A-10B%2B10A%2B17B=-50%2B60
7B=10
highlight%28B=10%2F7%29liters
Then from eq. 1,
A%2B10%2F7=5
A=35%2F7-10%2F7
highlight%28A=25%2F7%29 liters