Because
rate = distance/time
r = [tex] \frac{4 miles}{45 minutes} [/tex]
so it would be
r = [tex] \frac{4}{45} [/tex] miles per minute
Or if it was miles per hour:
[tex] \frac{4}{45} = \frac{x}{60} [/tex]
Cross multiplication gives us
45x = 240
[tex] \frac{16}{3} [/tex] mph
