Weekly Problem 45 - 2012
There are 10 girls in a mixed class. If two pupils are selected, the probability that they are both girls is 0.15. How many boys are in the class?
If two girls each take a sweet from each other's bags, what is the probability that they end up with what they started with?
6 tiles are placed in a row. What is the probability that no two adjacent tiles have the same letter on them?
Weekly Problem 43 - 2012
Four cards from a set numbered 1-36 are dealt. What is the probability that they are dealt in order?