SOLUTION: How many liters of what must be added to 20 liters of 15% salt solution to make 10% salt solutoin?

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Question 394397: How many liters of what must be added to 20 liters of 15% salt solution to make 10% salt solutoin?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
To make the solution less concentrated, water must be added.
In words:
(total salt)/(total solution) = 10%
Let a = liters of water to be added
given:
.15%2A20+=+3 liters salt
-------------------
3%2F%28a+%2B+20%29+=+.1
3+=+.1%2A%28a+%2B+20%29
3+=+.1a+%2B+2
.1a+=+1
a+=+10
10 liters of water must be added
check:
3%2F%2810+%2B+20%29+=+.1
3%2F30+=+.1
.1+=+.1
OK