algebra
posted by Deja .
How many liters of 20% alcohol solution should Maria mix with 50 liters of a 60% alcohol solution to obtain a 30% solution?

ok, in the 50 liters, you get 30 liters of alcohol content. In the final mixture, you want 30 percent, so
.30(V+50)=30+.2V
check that. solve for V, the volume of 20percent. 
Perfect thx!!