SOLUTION: Some 5% alcohol Solution is mixed with another 20% alcohol solution to get a mixture of 25 liters of 14% solution. Find the amount of each alcohol solution before mixing.

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Question 214085: Some 5% alcohol Solution is mixed with another 20% alcohol solution to get a mixture of 25 liters of 14% solution. Find the amount of each alcohol solution before mixing.
Found 2 solutions by nerdybill, josmiceli:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Some 5% alcohol Solution is mixed with another 20% alcohol solution to get a mixture of 25 liters of 14% solution. Find the amount of each alcohol solution before mixing.
.
Let x = amount of 5% solution
then because the total mixture is 25 liters we have
25-x = amount of 20% solution
.
Our equation:
.05x + .20(25-x) = .14(25)
.05x + 5 - .20x = 3.5
5 - .15x = 3.5
-.15x = -1.5
x = 10 liters (5% alcohol solution)
.
20% alcohol solution:
25-x = 25-10 = 15 liters

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let a = liters of 5% solution
Let b = liters of 20% solution
given:
(1) a+%2B+b+=+25
Alcohol in 5% solution = .05a
Alcohol in 20% solution = .2b
-------------------------------------
%28.05a+%2B+.2b%29%2F25+=+.14
.05a+%2B+.2b+=+3.5
(2) 5a+%2B+20b+=+350
Multiply both sides of (1) by 5 and subtract from (2)
(2) 5a+%2B+20b+=+350
(1) -5a+-+5b+=+-125
15b+=+225
b+=+15
and, since
a+%2B+b+=+25
a+%2B+15+=+25
a+=+10
15 liters of 5% solution and 10 liters of 20% solution are needed
check:
.05a+%2B+.2b+=+3.5
.05%2A10+%2B+.2%2A15+=+3.5
.5+%2B+3+=+3.5
3.5+=+3.5
OK