Answer:
The average speed of the plain was 800 miles/h.
Step-by-step explanation:
To solve this problem we first need to convert the time the tain took to finish the journey to hours. To do that we will divide the part that is in minutes by 60 and sum to the part that is in hours, we have:
time = 3 + 33/60 = 3 + 0.55 = 3.55 hours
The average speed is given by the following formula:
average speed = distance/time
average speed = 2840/3.55 = 800 miles/h
The average speed of the plain was 800 miles/h.