Answer:
230?
Explanation:
From what I found, the answer is 231, I'm assuming that the 231 in the question was a typo...
The system you are talking about is the solar system.
Most of Australia is dry and sunny, there are many desserts and dry areas, unless of course you live in Tasmania like myself where is usually pretty wet. Although we do have some hot weather (hot being 25 degrees celcius) which isn't nearly as hot as is it is on the mainland where it can get up to close to 50 degrees celcius!!
Well it depends on multiple things like the climate, amount of precipitation and so on like in a desert its gonna be hard to have run off because the water will just soak into the ground through its cracks because it doesn't get sufficient water supply. hope this helps.