Answer:
I guess that the question should say:
You need 3 scoops of powder lemonade mix to make two quarts of lemonade. How many scoops of powder lemonade mix are needed to make 3 gallons?
3 gallons = 12 quarts
if you need 3 scoops top make 2 quarts, then you will need (12/2) x 3 = 18 scoops of lemonade powder mix to make 3 gallons of lemonade.