Answer:
x = 6 gallons (of 30% alcohol)
y = 12 gallons (of 60% alcohol)
Step-by-step explanation:
Let
x = liters of 30% alcohol
y = liters of 60% alcohol
There are two unknowns, we need two equations
x + y = 18. (1)
0.30x + 0.60y = 0.50(x+y) (2)
From (1)
x + y = 18
y = 18-x
Substitute the value of y into (2) and solve for x:
0.30x + 0.60y = 0.50(x+y)
0.30x + 0.60(18-x) = 0.50(x+18-x)
0.30x + 10.8 - 0.60x = 0.50(18)
10.8 - 0.30x = 9
-0.30x = -1.8
Divide both sides by -0.30
x = 6 gallons (of 30% alcohol)
Substitute x=6 into (1) and solve for y:
x + y = 18
6 + y = 18
y = 12 gallons (of 60% alcohol)
