Problem solving: problems may be set which require problem solving based on information provided rather than knowledge about a topic.
This topic seems to involve describing some real life situation, often a slightly bizarre one, in such a way that you can write down and solve a set of simultaneous equations. If you get familiar with these questions you should find them pretty simple, and if one comes up it will be around five marks in the bank. But notice that there have been no such questions in the last two years: maybe people were getting too good at them.
Answers to problem solving questions