<PRE><B>Question 1052401</B>
A photographer is mixing a 5% acetic acid solution with a 10% acetic solution to get 5 liters of a 7%solution.
 How many liters of the 5 % and 10%solutions should he add?
:
let x = amt of 10% solution
the results is 5 liters, therefore 
(5-x) = amt of  5% solution
:
.10x + .05(5-x) = .07(5)
.10x + .25 - .05x = .35
.10x - .05x = .35 - .25
.05x = .10
x = .10/.05
x = 2 liters of the 10% solution
then obviously
5 - 2 = 3 liters of the 5% solution</PRE>