SOLUTION: In a chemistry class, 6 liters of a 12% alcohol solution must be mixed with a 20% solution to get a 14% solution. How many liters of the 20% solution are needed?

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: In a chemistry class, 6 liters of a 12% alcohol solution must be mixed with a 20% solution to get a 14% solution. How many liters of the 20% solution are needed?      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 273600: In a chemistry class, 6 liters of a 12% alcohol solution must be mixed with a 20% solution to get a 14% solution. How many liters of the 20% solution are needed?
Found 2 solutions by mananth, josmiceli:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
In a chemistry class, 6 liters of a 12% alcohol solution must be mixed with a 20% solution to get a 14% solution. How many liters of the 20% solution are needed?
Let the quantity of 20% solution be x liters
12%------------------20%-------------------14% mix
6-------------------- x--------------------x+6 (quantity)
Form an equation with actual parts mixed
0.12*6 + 0.2 x = 0.14(x+6)
0.72+0.2x = 0.14x+0.84
0.2x-0.14x=0.84-0.72
0.06x=0.12
x=2 liters which is the quantity of 20% alcohol required



Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
In words:
(liters of alcohol from 12% solution + liters of alcohol from 20% solution)/(total liters of final solution) = 14%
given:
.12%2A6+=+.72 = liters of alcohol in 12% solution
----------------------------------
Let x = liters of 20% solution needed
%28.72+%2B+.2x%29%2F%286+%2B+x%29+=+.14
.72+%2B+.2x+=+.14%2A%286+%2B+x%29
.72+%2B+.2x+=+.84+%2B+.14x
.06x+=+.84+-+.72
.06x+=+.12
x+=+2
2 liters of 20% solution are needed
check answer:
%28.72+%2B+.2x%29%2F%286+%2B+x%29+=+.14
%28.72+%2B+.2%2A2%29%2F%286+%2B+2%29+=+.14
%28.72+%2B+.4%29%2F8+=+.14
1.12%2F8+=+.14
1.12+=+.14%2A8
1.12+=+1.12
OK