a: What was the average speed of the winner of the wheelchair division? b: At this rate, about how long would it take this person to finish a 30-mile race?

Question

The record for the Boston Marathon's wheelchair division is 1 hour, 18 minutes, and 27 seconds. The Boston Marathon is 26.2 miles long.

 

 

a: round to the nearest hundredth

Answer 1

Speed is distance over time.  The unit for speed in this case will be miles per hour.  We already know the distance and time.  However, you have time in different units: hours, minutes, and seconds.  We want this overall time in only hours.

 

Know these conversion factors:

 

1 hr = 60 min

 

1 hr = 3600 sec

 

 

We will use these conversion factors to convert all units of time to hours.

 

 

 

18 minutes is 18/60 hours.  Or 3/10 hours.

 

27 second is 27/3600 hours.  Or 3/400 hours.

 

 

Now we add the each time segment.

 

1 hr + (3/10) hr + (3/400) hr = 1.3075 hrs

 

 

Divide 26.2 miles by 1.3075 hrs to get your speed in 26.2 miles.

 

Speed = (26.2 miles) / (1.3075 hrs) = 20.04 mph