There are six boxes containing 5, 7, 14, 16, 18, 29 balls of either red or blue in colour. Some boxes contain only red balls and others contain only blue.

One sales man sold one box out of them and then he says, "I have the same number of red and blue balls left over."

Which box is sold out?

He sold the box of 29 balls. Of the ones he has left, 18, 7, and 5 are red, and 14 and 16 are blue, or vice versa.

Posted by ethan on 2003-08-15 12:56:40