Question

A planet has a circular orbit around a star. It is a distance of 81,000,000 km from the centre of the star. It orbits at an average speed of 46,000 km/h. How many Earth days does it take the planet to orbit the star? Give your answer to 2 sf.

Answer 1

$81,000,000 \text{ km} \left(\frac{1 \text{ h}}{46,000 \text{ km}} \right) =\frac{40500}{23} \text{ h} \\ \\ \frac{40500}{23} \text{ h} \left(\frac{1 \text{ days}}{24 \text{ hours}} \right) \approx \boxed{73 \text{ days}}$