Question

light travels at a constant speed of 3x10^11 centimeters/sec. how long does it take light to reach the earth a distance of 1.5x10^8 kilometers give your answer in seconds and minutes.

Answer 1

If you get confused whether to multiply or divide, and using what, just remember that you are just changing units.

You have
speed = cm/s
and distance = cm
and you want time = s

so, divide cm by cm/s to cancel the cm and leave s

time = distance / speed

I assume you can plug in the numbers.

Answer 2

300,000,000