Question 310276
A chemist has 30 cc of a 12% solution of acid.
 He wishes to add enough water to make a 4% solution of acid.
 How many cubic centimeters of water must be added to the acid solution?
:
Let x = amt of water required
:
Write an "amt of acid equation" the amts are equal, only the percentage changes
.12(30) = .04(x+30)
3.6 = .04x + 1.2
3.6 - 1.2 = .04x
2.4 = .04x
x = {{{2.4/.04}}}
x = 60 cc of water required
:
:
Confirm the equality of the amt of acid
.12(30) = .04(60+30)
3.6 = .04(90)
3.6 = 3.6