Fruit punch mixtures added together

Question

A fruit punch that contains 25% fruit juice is combined with 100% fruit juice. How many ounces of each should be used to make 48 oz of a mixture that is 75% fruit juice

Answer 1

The sum of two variables x and y are 48 here and .25x+y=.75(x+y). So, .5x-.25y=0 or 2x=y. Plug this back into the sum and you get 3x=48  or x=16. So that's sixteen oz of .25 fruit juice and thirty two of  pure fruIt juice.