Answer:
Step-by-step explanation:
p=10(q-3r)/r
Cross multiply
pr = 10(q-3r)
pr = 10q - 30r
Pr + 30r = 10q
r(p + 30) = 10q
r = 10q/(p + 30)
You can determine your speed that is Speed = (distance/Time). Mind you in this cast time should be in hour, so 30 min - 1/2 hour or 0.5 Hour
Your speed is 5/0.5 = 10 mi/hour