Riddle: If place 1 cake of soap on a pan of a scale and 3/4 cake of soap and a 3/4-pound weight on the other, the pans balance.
How much does a cake of soap weigh?
Answer: Since 1/4 cake weighs 3/4 pound, and entire cake weighs 3 pounds.
A Cake of Soap Riddle Meme with riddle and answer link.