Answer:
2.38[tex]\frac{mi}{hr}[/tex]
Step-by-step explanation:
1. Change seconds to hours:
[tex]\frac{42in}{1sec} x \frac{3600sec}{1hr}[/tex] = 151200[tex]\frac{in}{hr}[/tex](seconds cancel out)
*because there are 3600 seconds in one hr, multiplying by 3600sec/1hr is basically multiplying by 1.
2. Change inches to miles:
151200[tex]\frac{in}{hr}[/tex] x [tex]\frac{1ft}{12in}[/tex] x [tex]\frac{1mi}{5280ft}[/tex] = 2.38[tex]\frac{mi}{hr}[/tex]
Make sure your units cancel out so you are left only with the units you want