To calculate how fast you need to travel, get the total distance, and
divide that by how much time you have. For example, your trip is 100
miles, and you need to complete the trip in 2 hours. To calculate how
many miles per hour you need to average, do the following:
distance = 100 miles
time = 2 hours
speed = 100 miles ÷ 2 hours = 50 miles/hours