Question

A newly discovered solar system is found 300 billion kilometers from the sun. How many AU does this represent? Show your work.

Answer 1

This is a conversion question. The surest way to do these is to set up a chart like this
It's like a fraction; multiply all the terms on the top then divide that by the terms on the bottom. So you plug in 300*10^9km in the top left and the number of km per AU in the bottom right giving:

Notice that the km cancel. You can also run through without any numbers (just the units) if you ever get a funny result check that you don't have something upside down.