Fake Coins Proof

You are a rare coins expert and have determined there are 7 fake coins out of 14 gold coins. Now you need to prove to the judge which ones are fake. It is known that that real coins all weigh…

Pulley Puzzle

In the pulley puzzle diagram below, there is a pulley attached to a scale. One side of the pulley is attached to a weight and the other side is attached to the ground. If the scale reads 100g, does the…

Escape the Maze

In this maze of 8×8 rooms, each room has an arrow that points up, down, left, or right – and it will only let you move to the adjacent room in the direction of the arrow. After you leave a…

How to Solve Rebus Puzzles

What are Rebus Puzzles? A rebus is a visual word puzzle that uses the positioning of words, letters, and/or symbols to represent a common phrase, sometimes in an indirect or tricky manner. They are sometimes referred to as “hidden meaning”…

Ants on a Stick

Six ants are walking at 1cm/second on a very narrow stick 100cm long: Ant 1: starts at 0, facing right Ant 2: starts at 20, facing right Ant 3: starts at 30, facing left Ant 4: starts at 40, facing…

Trailing Zeros

How many trailing zeros does 1000! have? “!” is the factorial symbol. For example, 12! = 12 x 11 x 10 x … x 2 x 1 = 479001600, which has 2 trailing zeros (zeros at the end of the…

Divisibility Rules

A divisibility rule is a shortcut you can use to see if an integer is evenly divisible by another integer, without doing the actual division. Most divisibility rules involve looking at the digits of the number. Here are some easy…