One canned juice drink is 2020% orange juice; another is 1010% orange juice. how many liters of each should be mixed together in order to get 1010l that is 1212% orange juice?

Let x represent the number of liters of 20% juice required.
.. 20%*x +10%*(10 -x) = 12%*10
.. 10x +100 = 120 . . . . . multiply by 100, eliminate parentheses
.. 10x = 20 . . . . . . . . . . subtract 100
.. x = 2

2 liters of 20% juice should be added to 8 liters of 10% juice to make 10 liters of 12% juice.

The household makes $424.45