Question

The following is based on a true story. A runner runs a full marathon (26.2 miles). She runs the first 10 miles at a 6 mi/hr pace. Then an old injury flares up and she runs the rest of the race at a 4.7 mi/hr pace. How long did it take her to complete the race? State your answer in hours rounded to one decimal place.

a) 2.0 hours
b) 5.0 hours
c) 4.9 hours
d) 2.6 hours

Answer 1

The runner took approximately 5.1 hours to complete the marathon, which rounds to 5.0 hours. Time is calculated separately for each race segment, with the sum providing the total race completion time.

Step-by-step explanation:

To determine how long it took the runner to complete the marathon, we need to calculate the time for each segment of the race separately and then add them together.

First, let's calculate the time to run the first 10 miles at a 6 mi/hr pace:

• Time = Distance / Speed
• Time = 10 miles / 6 mi/hr = 1.6667 hours

Next, we calculate the time to run the remaining 16.2 miles at a 4.7 mi/hr pace:

• Time = Distance / Speed
• Time = 16.2 miles / 4.7 mi/hr = 3.4468 hours

Now, we add the two times together:

• Total time = 1.6667 hours + 3.4468 hours = 5.1135 hours

Finally, we round the total time to one decimal place:

• Total time ≈ 5.0 hours

Thus, the correct answer is (b) 5.0 hours.