Final answer:
To show that Mr. Ghiorse was running at exactly 6.5 miles per hour at least twice during the Chicago Marathon, we can use the formula time = distance / speed. By calculating the time it takes him to complete the marathon and comparing it to his total running time, we can conclude that he must have been running at exactly 6.5 miles per hour for at least part of the race.
Step-by-step explanation:
To show that Mr. Ghiorse was running at exactly 6.5 miles per hour at least twice during the Chicago Marathon, we need to find the time it takes him to cover that distance at that speed.
First, we can use the formula to find the time it takes for a runner to complete a marathon: time = distance / speed. So, it takes him 26.2 miles / 6.5 miles per hour = 4.03 hours to complete the marathon.
Since his total running time is 3.75 hours, we can conclude that he must have been running at exactly 6.5 miles per hour or faster for at least part of the race, and therefore, he was running at exactly 6.5 miles per hour at least twice.