Question 104280
I try to use readily available conversion when I do it. 
3 feet = 1 yard
5280 feet = 1 mile
60 sec = 1 minute
60 minutes = 1 hour
{{{38(Yard/Sec)*(3 feet/1 Yard)*(1 mile/5280 feet)*(60 sec/1 minutes)*(60 minutes/1 hour)=77.7 (miles/hour)}}}