4 minutes 8 minutes 12 minutes 15 minutes
I gave my students this multiple choice question: An astronomical unit (AU) is the distance between Earth and the Sun. It takes about 8 minutes for the energy from the Sun to reach Earth. If Mars is 1.5 AU from the Sun, how many minutes will it take the Sun's energy to reach Mars?

Only one answer is correct among these 4 choices:
- 4 minutes
- 8 minutes
- 12 minutes
- 15 minutes

Could you tell me which one is correct?

12 minutes