How to execute the conversion process for this? What is the miles per hour and the feet per sec?

Question

Vance recently ran a marathon. It took him 5.2 hours to run the 26.2 miles required to complete a marathon. 

Find his average speed in miles per hour. Then convert his speed to feet per second. (Hint: 1 mile = 5,280 feet).

(Round your answers to two decimal places)

Answer 1

You can make a "daisy chain" of conversion factors that help in changing mi/hr to ft/sec. Notice how the units in the numerator and denominator of the intermediate fractions cancel out, leaving the ratio you want.

5.04 mi/1hr x 5280ft/1mi x 1hr/60min x 1min/60sec = 7.39ft/sec.

Easy to remember: 88 ft/sec = 60 mph. Can use in a proportion to convert:

88/x = 60/5.04 etc.

Answer 2

26.2/5.2 = 131/26 = 5.03846 = about 5.04 mph

1 mile = 5,280 feet

1 hour= 60 minutes

1 minute = 60 seconds

1 hour = 60x60= 3,600 seconds

26.2(5280)/5.2(3600) = about 7.39 feet per second