To determine how long it takes to travel 40 miles at a speed of 80 miles per hour, you can use the formula for time:
Time = Distance / Speed
In this case, the distance is 40 miles and the speed is 80 miles per hour. Plugging the values into the formula gives:
Time = 40 miles / 80 miles per hour = 0.5 hours
Since 0.5 hours is equivalent to 30 minutes, it will take you 30 minutes to travel 40 miles at a speed of 80 miles an hour.