Combinations

problem
The Olympic torch tour

Age

14 to 16

Challenge level

Imagine you had to plan the tour for the Olympic Torch. Is there an efficient way of choosing the shortest possible route?
problem
Teams

Age

16 to 18

Challenge level

Two brothers belong to a club with 10 members. Four are selected for a match. Find the probability that both brothers are selected.
problem
Spectrometry detective

Age

16 to 18

Challenge level

From the atomic masses recorded in a mass spectrometry analysis can you deduce the possible form of these compounds?