Question 1156558

How many gallons of 20% alcohol solution and 50% alcohol solution must be mixed to get 9 gallons of 30% alcohol solution?
<pre>Let amount of 20% solution be T
Then amount of 50% solution = 9 - T
We then get the following: .2T + .5(9 - T) = .3(9)
.2T + 4.5 - .5T = 2.7
.2T - .5T = 2.7 - 4.5
 - .3T = - 1.8
Amount of 20% solution, or {{{highlight_green(matrix(1,5, T, "=", (- 1.8)/(- .3), "=", 6))}}}
You should now be able to find the amount of 50% solution to mix!</pre>