There are five questions, worth 25 + 15 + 20 + 10 + 20 marks respectively. Notice that this means that all the questions together add up to 90 marks. If you're timing yourself (as you should) remember it's not 100 marks. Since you have 180 minutes this works out to 2 minutes per mark.
The five questions cover a number of areas:
The layout is not "easiest questions first", though we'd sort of like to do that. However, in order to give a reasonable layout on the pages, we had to re-order the questions somewhat.
What this means is that more than ever, you should make sure you read through the whole exam to find the questions you can do best, and do those first.