Category Archives: Probability

It’s just chance – or is it?


Searching for puzzle apps on my android phone, I encountered “Probability puzzles” by “atorch”. Nice puzzles, although this type of puzzle never was one of my favorites and probably never will be. The app is working well, and the puzzles are varied. Well recommended.

Probability actually has its root in betting and games of chance. I was reminded of this when I was downloading the “Print and play” game Fazenda. Unfortunately the dice were missing.
In the rules of Fazenda, there are three dice. All 18 sides are either brown or blue.

Three dice**/*****
This weeks problem is this
Suppose that the three dice are identical, and that they each have 2 brown and 4 blue sides, what is the chance that at least two brown sides come up?

New puzzles are published at least twice a month on Fridays. Solutions are published after one or more weeks. You are welcome to discuss difficulty levels, variations and alternate solutions, but plz. don’t publish the solutions. The solutions will be published after one or more weeks, and yes, we know that you are smarted than any one else.

You can check your solution here

Socks – again


Socks
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