Question 66951

Let x=amount of water to be added

Now we know that the amount of pure salt in the solution before the water is added (.72)(500) is equal to the pure salt in the solution after the water is added (.25)(500+x).  So our equation to solve is:

(.72)(500)=(.25)(500+x)  get rid of parens by multiplying out:

360=125+.25x  subtract 125 from both sides

360-125=125-125+.25x

235=.25x  divide both sides by .25
x=940 grams----------------amount of water to be added

CK

500(.72)=.25(500+940)
360=.25(1440)
360=360


Hope this helps-------ptaylor