# Probability - November 2005, Stage 3&4

## Problems

### Odds and Evens

##### Stage: 3 Challenge Level:

Is this a fair game? How many ways are there of creating a fair game by adding odd and even numbers?

### Flippin' Discs

##### Stage: 3 Challenge Level:

Identical discs are flipped in the air. You win if all of the faces show the same colour. Can you calculate the probability of winning with n discs?

### Cosy Corner

##### Stage: 3 Challenge Level:

Six balls of various colours are randomly shaken into a trianglular arrangement. What is the probability of having at least one red in the corner?

### Two's Company

##### Stage: 3 Challenge Level:

7 balls are shaken in a container. You win if the two blue balls touch. What is the probability of winning?

### The Better Bet

##### Stage: 4 Challenge Level:

Here are two games you have to pay to play. Which is the better bet?

### The Birthday Bet

##### Stage: 4 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 ?

### Bet You a Million

##### Stage: 4 Challenge Level:

Heads or Tails - the prize doubles until you win it. How much would you pay to play?

### Epidemic Modelling

##### Stage: 4 and 5 Challenge Level:

Use the computer to model an epidemic. Try out public health policies to control the spread of the epidemic, to minimise the number of sick days and deaths.