You can
put this solution on YOUR website!Let x=amount of water that must be added
Now we know that the amount of pure water added (x) plus the amount of pure water in the 50 liter acid solution (50)(0.70){if it's 30% acid, then it must be 70% water} must equal the amount of pure water in the final mixture (50+x)(0.80). So our equation to solve is:
x+(50)(0.70)=(0.80)(50+x) get rid of parens
x+3.5=4+0.80x subtract 0.80x and also 3.5 from both sides
x-0.80x+3.5-3.5=4-3.5+0.80x-0.80x collect like terms
0.20x=0.5 divide both sides by0.20
x=2.5 liters-------------amount of pure water that needs to be added
CK
2.5+3.5=4+2
6=6
Hope this helps---ptaylor
