# Car value

How the value of a car depreciates.

## Try

Select the button below to open the Python program in a new window. Run the program and read the lines of code to see if you can understand how it works. It will be helpful to arrange your display so that you can have this browser window on one side of the screen and the code on the other.

Watch this video to learn about the new concepts shown in the program:

## Investigate

Explain the purpose of the iteration and condition `while value >= resale_value and resale_value > 0:` in line 9.

The value of the car is recalculated until the value is less than the resale value and is also more than £0. The first condition stops when the resale value is reached and the second condition ensures the value cannot go below £0.

Explain why line 13 is not indented.

The final output statement about when to part exchange the car should not be inside the iteration because it needs to be executed after the year to part exchange has been calculated. This statement should only be output once, not after every calculation.

## Make

### Success Criteria

Change the program so that it:

1. Only allows the value of the car to be shown up to year 4. Cars cannot be part exchanged with this dealer after year 5.

#### Typical inputs and outputs from the program would be:

Enter the value of the car purchased: £8500

Enter the minimum part exchange value: £2000

In year 0 the car is worth £ 8500

In year 1 the car is worth £ 6375

In year 2 the car is worth £ 4781

In year 3 the car is worth £ 3585

In year 4 the car is worth £ 2688

Part exchange before the end of year 5

#### Knowledge Organiser

Use these resources to help you meet the success criteria if you need support or syntax reminders.

###### Notes:

while

Can also be used with mathematical operators and more than one condition.

The following operators can be used in conditions. They all return True or False:

==

Is equal to. E.g. ` while x == y` means repeat the indented code until x does not equal y.

!=

is not equal to. E.g. `while x != y` means repeat the indented code until x is the same as y.

<

Is less than. E.g. `while x < y` means repeat the indented code until x is not less than y.

>

Is greater than. E.g. `while x > y` means repeat the indented code until x is not greater than y.

<=

Is less than or equal to. E.g. `while x <= y` means repeat the indented code until x is not less than or equal to y.

>=

Is greater than or equal to. E.g. `while x >= y` means repeat the indented code until x is not greater than or equal to y.

The following Boolean operators can be used to join multiple conditions into a single selection statement that returns either True or False:

and

Both conditions must be True to continue the iteration.

or

One of the conditions must be True to continue the iteration.

not

The condition must be False to continue the iteration.

You can have as many conditions in one statement as you need. Use brackets () for order of prescedence.

## Evaluate

Run the unit tests below to check that your program has met the success criteria.

Enter the value of the car purchased: £20000

Enter the minimum part exchange value: £5000

In year 0 the car is worth £ 20000

In year 1 the car is worth £ 15000

In year 2 the car is worth £ 11250

In year 3 the car is worth £ 8437

In year 4 the car is worth £ 6327

Part exchange before the end of year 5

Enter the value of the car purchased: £12000

Enter the minimum part exchange value: £8500

In year 0 the car is worth £ 12000

In year 1 the car is worth £ 9000

Part exchange before the end of year 2

Enter the value of the car purchased: £20000

Enter the minimum part exchange value: £1000

In year 0 the car is worth £ 20000

In year 1 the car is worth £ 15000

In year 2 the car is worth £ 11250

In year 3 the car is worth £ 8437

In year 4 the car is worth £ 6327

Part exchange before the end of year 5

Enter the value of the car purchased: £35000

Enter the minimum part exchange value: £5000

In year 0 the car is worth £ 35000

In year 1 the car is worth £ 26250

In year 2 the car is worth £ 19687

In year 3 the car is worth £ 14765

In year 4 the car is worth £ 11073

Part exchange before the end of year 5

Craig ‘n’ Dave

In partnership with