| A(Alcohol), W(water), (M)Mixture | |||
| A | 40% | 80% | 50% |
| W | 60% | 20% | 50% |
| x | y | 40 Gallons | |
\(x+y = 40\)
\(x = 40-y\)
\(0.40x +0.80y = 0.50(40) \)
\(0.40(40-y) +0.80y = 0.50(40) \)
\(16 +0.4 y = 20 \)
\(y = 10\)
\(x = 40-10\)
\(x =30\)
Thus, to create a solution a 30 gallons is needed from the 40% solution and 10 gallons from the other.