math problem help...?

Question

john travels 15 miles/hour. what is the speed in feet/second?

i know that 1 mile = 5280 ft.....so 15 miles would be 79200

but the only available answers are 20ft/s, 10ft/s, 22ft/s, 18ft/s

can someone give the right answer and explain your steps how you got that answer???

Answer 1

You're on the right track...
You converted miles into feet.
Now convert hours into seconds (1hr=3600sec)
and simplify 79200ft/3600sec to get your answer.

Answer 2

now, divide those 79200 feet by the 3600 seconds that you have in an hour and that will be your answer: 22ft/sec