3 out of 3
How many different phone numbers are there starting with a 3 and with at most two different digits?
1 out of 3
Five equations and five unknowns. Is there an easy way to find the unknown values?
1 out of 3
Investigate the transformations of the plane given by the 2 by 2 matrices with entries taking all combinations of values 0, -1 and +1.
1 out of 3
Take three whole numbers. The differences between them give you three new numbers. Find the differences between the new numbers and keep repeating this. What happens?
1 out of 3
How would you design the tiering of seats in a stadium so that all spectators have a good view?
1 out of 3
How can you quickly sort a suit of cards in order from Ace to King?
1 out of 3
Can you work out where these 5 riders came in a not-quite-so-famous bike race?
2 out of 3
In 1% of cases, an HIV test gives a positive result for someone who is HIV negative. How likely is it that someone who tests positive has HIV?
3 out of 3
DNA profiling is an invaluable tool for the police. However, when it comes to probability, things aren't always as straightforward as they seem.
3 out of 3
Try to solve this very difficult problem and then study our two suggested solutions. How would you use your knowledge to try to solve variants on the original problem?
