What is the gal of the 80% pesticide solution is needed to make a final solution that is 60% pesticide

What is the gal of the 80% pesticide solution is needed:
let x = amt of 80% stuff required = 80/100 = 0.8
amount of 60% stuff required = 60/100 = 0.6
A simple mixture equation in decimal form
[tex]\begin{gathered} 0.8x+0.2(40)=0.6(x+40) \\ 0.8x+8=0.6x+24 \\ 0.8x-0.6x=24-8 \\ 0.2x=16 \\ x=\frac{16}{0.2} \\ x=80 \end{gathered}[/tex]