In a chemistry​ class, 16 liters of a 11​% alcohol solution must be mixed with a 20​% solution to get a 12​% solution. How many liters of the 20​% solution are​ needed?

Answer 1

Let x = # of liters of the 20% solution that are needed

0.12 = (16*0.11 + x*0.20) / (16+x)

0.12*16 + 0.12x = 16*0.11 + x*0.20

16(0.12-0.11) = 0.08*x

16(0.01) = 0.08*x

x = (16*0.01) / 0.08

x = 2

Answer: 2 Liters of the 20% solution are needed.