Speed rate = distance / time
Distance 1 = 4 miles
time 1 = 2 minutes
Distance 2 = 1 mile
Time 2 = 12 minutes
Time difference : (12-2 ) = 10 minutes
Distance = 4-1 = 3 miles
speed rate = 3 miles / 10 minutes = 0.3 miles per minute
To obtain it in miles per hour:
10 min / 60 = 1/6 hours
rate = 3 miles / (1/6 ) hours = 18 miles per hour
