1. ## Percentage word problem [SOLVED]

How many kilograms of pure salt must be added to 5 kg of a 20% salt solution in order to produce a 25% solution?
I'm not sure how to set up the equations for this type of problem. This is my guess at the equations, but it came out with a negative answer which didn't seem right.

Code:
s + 4w = .2
s + w = 5

Thanks for any help

2. If you let x=the amount of pure salt, then you have:

$x+.20(5)=.25(5+x)$

Solve for x.

3. Thanks for the quick reply, I think I understand it now.