Question 154049
There are 3600 seconds in an hour.
There are 5280 feet in a mile.

75seconds | 1 minute  |   1 hour   | 5280 feet
500 feet  | 60 seconds| 60 minutes | 1 mile

All you have to do is multiply across. This shows how you go from seconds to hours and feet to miles. Cross out any labels that are on both top and bottom so you end up with

75  | 1  | 1 hour | 5280
500 | 60 |   60   | 1 mile 

Now multiply across on the top and across on the bottom so you end up with

396,000 hour
1,800,000 mile

Reduce your fraction

11
50

You end up with .22 when you divide. 

Your answer in two significant digits is .22 miles/hour