This is straight out of a maths competition. One of the few questions I can't manage to get a grip on.
Luisa cycled to and from a destination using the same route. The route included some flat roads and hills.
On the flat road she averaged 40km/h, uphill she averaged 30km/h and downhill she averaged 60km/h.
The whole journey took six hours.
What was the total distance travelled by Luisa, in km?