Five 3's can express 37 :-

37 = 33 + 3 + 3/3.

Find another way to do it.

# Plep's Puzzles

## Tuesday, February 27, 2007

## Monday, February 19, 2007

### Not about polar bears

There's a well-known puzzle which is :- 'A bear hunter walks one mile south, one mile east, and one mile north, only to find himself back at his starting point. What colour is the bear he's hunting?'

The traditional answer is 'white' because with a starting point of the North Pole, someone walking one mile south, one mile east, and one mile north will find themselves back at the North Pole. Therefore the bear he's hunting must be a polar bear.

There are, however, a number of other points on the Earth's surface from where someone walking one mile south, one mile east, and one mile north will find themselves back at their starting point. Where are they?

## Tuesday, February 13, 2007

You have 50 pound coins on the table in front of you. You are blindfolded and cannot discern whether a coin is heads up or tails up by feeling it. You are told that x coins are heads up, where 0 < x < 50. You are asked to separate the coins into two piles in such a way that the number of heads up coins in both piles is the same at the end. You may flip any coin over as many times as you like. How will you do it?