Conditional probability

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
Drug testing

Age

16 to 18

Challenge level

How do different drug-testing regimes affect the risks and payoffs for an athlete who chooses to take drugs?
problem
Non-transitive dice

Age

11 to 14

Challenge level

Alison and Charlie are playing a game. Charlie wants to go first so Alison lets him. Was that such a good idea?
problem
Ante up

Age

16 to 18

Challenge level

Use cunning to work out a strategy to win this game.
problem
At least one...

Age

11 to 14

Challenge level

Imagine flipping a coin a number of times. Can you work out the probability you will get a head on at least one of the flips?
problem
Mathsland national lottery

Age

14 to 16

Challenge level

Can you work out the probability of winning the Mathsland National Lottery?
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
Dicey dice

Age

16 to 18

Challenge level

Invent a set of three dice where each one is better than one of the others?
problem
X-dice

Age

16 to 18

Challenge level

Explore these X-dice with numbers other than 1 to 6 on their faces. Which one is best?