SOLUTION: 2. 15 gallons of a 20% acid solution is to be mixed with a 12% acid solution to yield an 18% acid solution. How many gallons of the 12% acid solution will be needed?

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Question 953330: 2. 15 gallons of a 20% acid solution is to be mixed with a 12% acid solution to yield an 18% acid solution. How many gallons of the 12% acid solution will be needed?


Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
5 gallons of a 20% acid solution is to be mixed with a 12% acid solution to yield an 18% acid solution.
How many gallons of the 12% acid solution will be needed?
:
let = amt of 12% acid required
then
(x+5) = resulting amt of the 18% solution
:
A mixture equation in decimal form
.20(5) + .12x = .18(x+5)
1.0 + .12x = .18x + .90
1.0 - .90 = .18x - .12x
.1 = .06x
x - .1/.06
x = 12%2F3 gal of 12% solution
:
:
Check this on your calc:
enter .2(5) + .12(1.6667)
then
enter .18(1.6667+5)