A random assortment of maths problems with recurring characters.

## Percentage error

Lily estimates Aarav's height to be 165cm.

Actually he is 160cm tall.

The error in her estimate is the difference:

`error = 165cm - 160cm = 5cm`

The *percentage error* is the error, 5cm, as a percentage of the actual height, 160cm:

```
percentage error = 5160× 100%
= 3.125%
```

Now, suppose a noisy miner bird estimates a magpie's height as 45cm.

If the magpie is actually 40cm tall, again the error is 5cm:

`error = 45cm - 40cm = 5cm`

What is the percentage error?

## Exponential Growth

If the sharing continues at this rate,

how many people will have seen the video after one hour?