### Percentage Unchanged

If the base of a rectangle is increased by 10% and the area is unchanged, by what percentage (exactly) is the width decreased by ?

### CD Heaven

All CD Heaven stores were given the same number of a popular CD to sell for £24. In their two week sale each store reduces the price of the CD by 25% ... How many CDs did the store sell at each price?

### A Change in Code

There are two sets of numbers. The second is the result of the first after an increase by a constant percentage. How can you find that percentage if one set of numbers is in code?

# The Legacy

##### Stage: 4 Challenge Level:

 Your school has been left $£ 1 \; 000 \; 000$ in the will of an ex-pupil ...

The pupil made some conditions on how the money should be invested and used. These were:
• The money should have a lifetime of $50$ years.
• That the school benefits in some way (spends part of the investment) every year.

You are asked to produce models of investment and expenditure based on any balance being invested at a fixed interest rate (it is suggested that you could start with a rate of $4 \%$). Your model could also consider different inflation rates.

What model would you choose to ensure the best return for the school over a period of $50$ years?

If you want some suggested starting points for models you might like to look at these .