### Rule of Three

If it takes four men one day to build a wall, how long does it take 60,000 men to build a similar wall?

### Crossing the Atlantic

Every day at noon a boat leaves Le Havre for New York while another boat leaves New York for Le Havre. The ocean crossing takes seven days. How many boats will each boat cross during their journey?

### On Time

On a clock the three hands - the second, minute and hour hands - are on the same axis. How often in a 24 hour day will the second hand be parallel to either of the two other hands?

# The Lady or the Lions

##### Age 11 to 14 Challenge Level:

Whenever the peasant has to make a choice of which way to go he has 3 choices and no way of knowing which route to take. Assume he chooses randomly and work out the probability of him reaching chamber A and the probability of him reaching chamber B. The clever princess has seen the map and worked out which chamber he is more likely to end up in so she waits there knowing that then the story is more likely to end up happily ever after.

Xing Cong gave the solution that the princess should wait in A because the probability of the peasant arriving in A is 5/9, and he sent this diagram.