### Gambling at Monte Carlo

A man went to Monte Carlo to try and make his fortune. Is his strategy a winning one?

### Marbles and Bags

Two bags contain different numbers of red and blue marbles. A marble is removed from one of the bags. The marble is blue. What is the probability that it was removed from bag A?

### Coin Tossing Games

You and I play a game involving successive throws of a fair coin. Suppose I pick HH and you pick TH. The coin is thrown repeatedly until we see either two heads in a row (I win) or a tail followed by a head (you win). What is the probability that you win?

# Jewellery Boxes

##### Stage: 4 Short Challenge Level:
See all short problems arranged by curriculum topic in the short problems collection

Two boxes, P and Q, each contain 3 jewels.
When a jewel worth £5000 is transferred from P to Q, the average value of the jewels in each box increases by £1000.
What is the total value of all six jewels?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

This problem is taken from the UKMT Mathematical Challenges.