Answer:
18 gallons from container [tex]a[/tex] and 22 gallons from the container [tex]b[/tex] to be mixed to get the required mixture.
Step-by-step explanation:
Given that the container [tex]a[/tex] has 20% concentrated cleaner
and container [tex]b[/tex] has pure water which has 0% cleaner.
Let x gallons from container a and y gallons from the container b are mixed to get a 9% concentrated solution.
So,
[tex]9\%\; \text{of}\; (x+y) = (20\% \; \text{of}\; x )+(0\% \; \text{of}\; y)\cdots(i)[/tex]
As the total amount of the final solution= 40 gallons
So, [tex]x+y=40\cdots(ii)[/tex]
Using the value of equation (ii) in equation (i), we have
9% of 40 = 20% of x
[tex]\Rightarrow 0.09\times 40=0.2 \times x[/tex]
[tex]\Rightarrow x=\frac{0.09\times 40}{0.2}[/tex]
[tex]\Rightarrow x=18[/tex] gallons.
From equation (ii),
18+y=40
[tex]\Rightarrow y=40-18=22[/tex] gallons.
Hence, 18 gallons from container [tex]a[/tex] and 22 gallons from the container [tex]b[/tex] to be mixed to get the required mixture.