Question 1101674
Let C denote the 19% solution and D denote the final 21% solution.
We have 8 lbs of 22% solution.
Using the method of alligation.
1= 21 - 22
2= 19 - 21
E.g. There are 2 parts of C for every 1 parts of D
then there are 8 parts of z, since (2/1)=8/z
x= 4= 8/(2/1) lbs of 19% solution to add to your 8 lbs of 22% solution.
y= 12= (8+4) lbs of the final 21% solution.
check
0.19 * 4 + 0.22 * 8 = 0.21*(8+4)
0.76 + 1.76 = 0.21*(12)
2.52 = 2.52
ok
<pre>
22         2       8 lbs of 22% solution
      21          12 lbs of 21% solution
19         1 1/2*8=4 lbs of 19% solution
           3
</pre>