Question 1066435
Please help with mixture problem. I can't figure out how to get the equation. Thanks! 
<pre>
A chemist needs 70mL of a 32% solution, but has only 26% and 
47% solutions available. Find how many mL of each that should 
be mixed to get the desired solution. 

An N% solution is some liquid which is N% pure stuff and the 
rest water.  Make this chart:

                  |  mL  |   %   |mL of
                  |  of  |  as   |pure
                  |liquid|decimal|stuff
------------------------------------------- 
Weaker solution   |   x  | 0.26  |0.26*x
Stronger solution |   y  | 0.47  |0.47*y
-------------------------------------------
Desired solution  |  70  | 0.32  |0.32*70

The equations come from the two end columns:

{{{system(x+y=70,0.26*x+0.47*y=0.32*70)}}}

The second equation simplifies to

26x + 47y = 2240

solve for x and y.

Edwin</pre>