How many ounces

Question

How many ounces of pure cranberry juice and how many ounces of a citrus fruit drink containing 10% fruit juice should be mixed to get 90 ounces of a fruit drink that is 20% fruit juice

Answer 1

p = ounces of pure juice (100%)

90 - p = ounces of 10% juice

 

Set this up as a combination of the percentages weighted by the number of ounces.

 

p(100%) + (90 - p)(10%) = 90(20%)

 

Solve for p.

 

100p + 900 - 10p = 1800

90p = 1800 - 900 = 900

90p = 900

 

p = 10 ounces