Question

If Mars is 225 million kilometers from the sun, how long does it take light from the sun to reach Mars?

Answer 1

We already know that the speed of light is 299,792 km/s.

225,000,000 km* (1 s/ 299,792 km) ≈ 751 s.
(Note that the unit cancels out so you get the answer)

It takes light about 751 seconds from the Sun to reach Mars~