A coin is flipped 4 times. What is the probability of getting heads at least 3 times?

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?

How many different ways can I arrange the CDs in my collection?

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 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?