Category Archives: Probability

Socks – again

In one of the earliest posts I listed a number of puzzles on socks. Here is another one:

1) Socks in a bag
You put two socks in a bag. For every sock you put in, there is a 50% chance that it is blue and a 50% chance that it is red. I don’t see which colours you put into the bag.
Without looking, I take out one sock and it turns out to be blue. What is the chance that the other is also blue?

If you are puzzled, we have a solution for you.


Two sons

DiceThis weeks puzzle is a simple chance problem. One of my sons has a one out of four chance to win one or perhaps even two medals at skating this weekend. My other son this weekend has a 1 out of 3 chance to win a medal.

What is the chance that at least one of them wins a medal this weekend?

You can check your solution