What do I need to know about modelling with progressions?
Many real-life situations can be modelled using progressions
If a quantity is changing repeatedly by having a fixed amount added to or subtracted from it then the use of arithmetic progressions is appropriate
If a quantity is changing repeatedly by a fixed percentage, or by being multiplied repeatedly by a fixed amount, then the use of geometric progressions is appropriate
Exam Tip
Remember, an exam question won't always tell you to use progression methods, so you've got to be able to spot 'hidden' progression questions.
To help you do this, be suspicious of questions about savings accounts, salaries, sales commissions, profits and the like – these are often progression questions in disguise!