Multiplication and division skills are useful when solving speed, distance and time problems. It may be useful to review how to calculate speed, distance and time.

What is speed? Definition. Units of speed. Calculate one of distance, speed or time given the other two variables.

For example, if you know the speed of any vehicle and the distance covered by that vehicle, then you can easily calculate the time taken for the entire journey by using the above formula.

But using speed to calculate distance leaves no way to calculate any “peculiar motion” the galaxy might have in addition to the motion that is part of the overall expansion.