<PRE><B>Question 561723</B>
Gus has on hand a 5% alcohol solution and a 20% alcohol solution.
 He needs 30 liters of a 10% alcohol solution.
 How many liters of each solution should he mix together to obtain the 30 liters?
:
There is an easier way to do this
let x = 20% solution
then since the result is to be 30 liter:
(30-x) = 5% solution
:
A typical mixture equation
:
.20x + .05(30-x) = .10(30)
.20x + 1.5 - .05x = 3
.20x - .05x = 3 - 1.5
.15x = 1.5
x = {{{1.5/.15}}}
x = 10 liters of 20% solution
then
30-10 = 20 liters of 5% solutions
:
;
Check this
.2(10) + .05(20) = .10(30)
2 + 1 = 3; confirms our solutions solution of 10 and 20</PRE>