Question

A bus travels 20 km in 30 minutes. What is the average speed of the bus?

The answer is 40 km/h but how do I figure that out?

Answer 1

20/30 = x / 60.....20 km to 30 min = x km to 60 min (because there is 60 minutes in an hr)

u will then cross multiply because this is a proportion
(30)(x) = (20)(60)
30x = 1200
x = 1200/30
x = 40........so 20 km in 30 min = 40 km in 60 min(per hr)

Answer 2

20 / 0.5 = 40


30 minutes is 0.5 as a decimal. You then do Distance / Time to get your answer.