6 Oil is leaking into the sea from a pipeline, creating a circular oil slick. The radius \(r\) metres of the oil slick \(t\) hours after the start of the leak is modelled by the equation
$$r = 20 \left( 1 - \mathrm { e } ^ { - 0.2 t } \right) .$$
- Find the radius of the slick when \(t = 2\), and the rate at which the radius is increasing at this time.
- Find the rate at which the area of the slick is increasing when \(t = 2\).