Question

The speed of light is about 3.00 x 10^5 km/s. It takes approximately 1.28 seconds for light reflected from the moon to reach Earth. What is the average distance from Earth to the moon?

Answer 1

Average distance from Earth to the moon = speed of light x time 
                                                                       = 3 x 10^5 x 1.28
                                                                       = 384000 km. 

Hence the average distance from Earth to the moon is 384000 km. 
Hope this helps, have a great day ahead!