SOLUTION: How much pure salt must be added to to 25 grams of a 12% salt solution to make it a 20% solution. I am having a very hard time trying to figure this problem out. Thanks for your

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Question 27219: How much pure salt must be added to to 25 grams of a 12% salt solution to make it a 20% solution. I am having a very hard time trying to figure this problem out. Thanks for your help.
Dennis

Found 3 solutions by Paul, MathTherapy, josgarithmetic:
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
25(12)=20(x+25)
300=20x+500
20x=200
x=10

Hence, about 10grams is needed.
Paul.

Answer by MathTherapy(10719) About Me  (Show Source):
You can put this solution on YOUR website!
How much pure salt must be added to to 25 grams of a 12% salt solution to make it a 20% solution.  I am having a very hard time
trying to figure this problem out.  Thanks for your help.

Dennis

With amount of pure salt being S, equation is: .12(25) + S = .2(25 + S)
Solving for S, amount of pure salt to be added = 2%261%2F2, or 2.5 grams.

FYI: The answer is NOT 10 grams, as the other person who responded, states!

Answer by josgarithmetic(39730) About Me  (Show Source):
You can put this solution on YOUR website!
x amount of pure salt to add

%280.12%2A25%2Bx%29%2F%2825%2Bx%29=0.2
-
x%2B0.12%2A25=0.2%2825%2Bx%29
x%2B0.12%2A25=0.2%2A25%2B0.2x
x-0.2x=0.2%2A25-0.12%2A25
x%281-0.2%29=25%280.2-0.12%29
x=25%28%280.2-0.12%29%2F%281-0.2%29%29
.
.