Answer to Math Olympiad #4

Problem:

If 24 gallons of water are poured into an empty tank, then ¾ of the tank is filled.  How many gallons does a full tank hold?

Solution:

If ¾ of the tank contains 24 gallons, then ¼ of the tank contains 1/3 of 24 or 8 gallons.  Thus 4/4, being a full tank, contains 4x8 or 32 gallons.