Question 155666
Let x = the number of liters of 10% alcohol solution to be added to 70 liters of 90% alcohol solution to get (x+70) liters of 30% alcohol solution.
After changing the percentages to their decimal equivalents, we can express this as:
(0.1)x + (0.9)(70) = (x+70)(0.3) Simplify this and solve for x.
0.1x+63 = 0.3x+21 Subtract 0.1x from both sides.
63 = 0.2x+21 Subtract 21 from both sides.
42 = 0.2x Finally, divide both sides by 0.2
x = 210 liters.
You would need to mix 210 liters of a 10% alcohol solution to 70 liters of 90% alcohol solution to obtain 280 (210+70) liters of 30% alcohol solution.