The area (A) of a rectangular enclosure of length \(x\) metres is given by \(A=x(6-x)\), as shown in the adjacent diagram.

What is the maximum area of the enclosure?

The equation \(d=0.004s(s-1)\) is used to model the stopping distance of a train, where \(d\) is the stopping distance in metres and \(s\) is the train's speed in km/h. What is the stopping distance when the train is travelling at 40 Km/h?

The equation \(d=0.004s(s-1)\) is used to model the stopping distance of a train, where \(d\) is the stopping distance in metres and \(s\) is the train's speed in km/h. What is an estimate of the maximum speed (km/h) that a train could be travelling to stop within 40 m?

The equation \(d=0.004s(s-1)\) is used to model the stopping distance of a train, where \(d\) is the stopping distance in metres and \(s\) is the train's speed in km/h. What is the difference between the stopping distances when a train is travelling at 60 km/h to travelling at 80 km/h?

The equation \(d=0.004s(s-1)\) is used to model the stopping distance of a train, where \(d\) is the stopping distance in metres and \(s\) is the train's speed in km/h. What is the stopping distance when the train is travelling at 50 km/h?