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?

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%