How does the answer equal 2km?

Question

How many kilometers can a greyhound run in four minutes if it runs half as fast as a car going 60km/h? You use the Distance, Time, Speed method. So if the greyhound runs half as fast as a car (60km/h) it would run at 30km/h, no? And if it runs for 4min then 4min x 30km/h = 120km? How am I not understanding this?

Answer 1

You have to convert the speed to kilometers per MINUTE.

 

30 km/hour * 1 hour/60 min = 1/2 km  per minute

 

So in 4 minutes, the greyhounds runs 2 kilometers

Answer 2

You have to use consistent time units. Four minutes is 1/15 hr