A teacher gave his students the following advice about how to organise their time:

• 1. You should be asleep for 6 hours every day;
• 2. You should spend the same amount of time studying at home as you spend in lessons;
• 3. You should not spend more than 3 hours a day playing computer games.

A student drew a pie chart to represent this advice, using sections for sleep, studying at home, studying in lessons, playing computer games and a section for all other activities.