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?

Weekly Problem 48 - 2014

Two of the triangles in the diagram are shaded black. What is the probability the resulting figure has at least one axis of symmetry?

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?

If you take two dominoes from a set at random, what is the probability that they 'match'?

Weekly Problem 43 - 2012

Four cards from a set numbered 1-36 are dealt. What is the probability that they are dealt in order?