Question

One canned juice drink is 25​% orange​ juice; another is 5​% orange juice. How many liters of each should be mixed together in order to get 20L that is 7​% orange​ juice?

Answer 1

x+y=20
25%x+5%y=7%*20 => 0.25x+0.05y=1.4
miltiply every term in equaition one with 0.25: 0.25x+0.25y=5
subtract equation two from the new equation: 0.20y=3.6
y=18
x=2
2 liters of the 25% and 18 liters of the 5%