How many liters of a 60​% acid solution must be mixed with a 20​% acid solution to get 400 L of a 50​% acid​ solution?

Answer 1

(x L)(60%) + (400-x L)(20%) = (400 L)(50%)

60x + 8000 - 20x = 20,000

40x = 12,000

x = 300 liters of 60%