Question

25) One canned juice drink is 15% orange juice; another is 5% orange juice. How many liters of each should be mixed together in order to get 10L that is 12% orange juice.

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Answer 1

Let A be the 15% canned juice and B be 5% juice
Va + Vb = 10
Vb = 10 - Va
Concentration of final solution = 12% juice
10 x 0.12 = Va x 0.15 + Vb x 0.05
Substituting Vb from the first equation:

1.2 = 0.15Va + 0.5 - 0.05Va
Va = 7 liters
Vb = 3 liters

7 liters of the 15% juice and 3 liters of the 5% juice.