Conditional probability

problem
In a box

Age

14 to 16

Challenge level

Chris and Jo put two red and four blue ribbons in a box. They each pick a ribbon from the box without looking. Jo wins if the two ribbons are the same colour. Is the game fair?
problem
The birthday bet

Age

14 to 16

Challenge level

The next ten people coming into a store will be asked their birthday. If the prize is £20, would you bet £1 that two of these ten people will have the same birthday ?
problem
Same number!

Age

14 to 16

Challenge level

If everyone in your class picked a number from 1 to 225, do you think any two people would pick the same number?
problem
Mathsland national lottery

Age

14 to 16

Challenge level

Can you work out the probability of winning the Mathsland National Lottery?
problem
Winning marble

Age

14 to 16

Challenge level

How can this prisoner escape?
problem
Dropouts

Age

14 to 16

Challenge level

What percentage of students who graduate have never been to France?
problem
Do you brush your teeth every day?

Age

14 to 18

Challenge level

How can we find out answers to questions like this if people often lie?
problem
Snooker

Age

16 to 18

Challenge level

A player has probability 0.4 of winning a single game. What is his probability of winning a 'best of 15 games' tournament?
problem
Snooker frames

Age

16 to 18

Challenge level

It is believed that weaker snooker players have a better chance of winning matches over eleven frames (i.e. first to win 6 frames) than they do over fifteen frames. Is this true?
problem
Succession in Randomia

Age

16 to 18

Challenge level

By tossing a coin one of three princes is chosen to be the next King of Randomia. Does each prince have an equal chance of taking the throne?