The speed of light is about 3.00 * 105 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?

Just to correct you - the speed of light is 3.0 x 10^5 km/sec and not 105 km/sec as given by you (maybe it was just a typing mistake from your end).

The average distance between earth and moon would be - 384,000 kms.

This is calculated by the formula - > Distance = Speed x Time.