SOLUTION: A 20 gallon salt solution is 30% salt. What is the greatest number of gallons of water that can be evaporated so the solution is still less than 45% salt?

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Question 100891: A 20 gallon salt solution is 30% salt. What is the greatest number of gallons of water that can be evaporated so the solution is still less than 45% salt?
Answer by ankor@dixie-net.com(12701) (Show Source):
You can put this solution on YOUR website!
A 20 gallon salt solution is 30% salt. What is the greatest number of gallons of water that can be evaporated so the solution is still less than 45% salt?
:
Let x = amt of water evaporated to provide a 45% solution
.3(20) < .45(20-x)
:
6 - < 9 - .45x
:
+.45x < 9 - 6
:
.45x < 3
:
x < 3/.45
:
x < 6 gal evaporated to maintain less than a 45% solution
:
:
Check by finding salt content in the two amts:
.3(20) = .45(20 - 6)
6 = .45 * 13
6 = 6