human
Emma traveled by car 280 miles in 2 hours 20 minutes. What was the average speed of the car in miles per hour?
assistant
How many minutes are in 4 hours 20 minutes? ** We first convert the time of 4 hours 20 minutes in minutes 2 hours 20 minutes = 2 × 60 + 20 = 140 minutes
How many miles per minute is the average speed? ** Average speed S is given by distance / time. Hence S = 280 miles / 140 minutes = <<280/140=2>>2 mile / minute
How many miles per hour is the average speed? ** There are 60 minutes in an hour so the speed is 2*60=120 miles/hour
#### 120