When James was nine years old he hammered a nail into a tree to mark his height. Ten years later, James returned to see how much higher the nail was. If the tree grew by four inches each year, how much higher would the nail be?
Riddle AnswerHard Riddles
5 to 2 Squares Matchstick Puzzle
There are five squares formed by 12 matchsticks as shown in the figure. Can you remove just two matchsticks so that only two squares remain?
Ping Pong Ball in a Hole
A ping pong ball fell down into a narrow metal pipe embedded in concrete one foot deep. You have a table tennis racket (bat or paddle), a pair of shoe laces and a large unopened water bottle, which does not fit into the pipe. How can you get the ping pong ball out of the pipe undamaged?
Riddle AnswerSliding Coins
Three pennies and three nickles are arranged in a row. The pennies are red and nickles are green in color. The goal is to move them so that the coins are again in a row, with all pennies to the right and nickels to the left.
Each move consists of moving a pair of adjacent coins, and sliding those two coins to a new position without rotating the coins. How can you achieve this (shown below) in three moves?
12 Marbles Problem
You have twelve marbles that are identical in size, shape, and color. One of the marbles is heavier in weight than the rest. How can you find the heavier marble by using a balance scale only thrice?
Riddle Answer