Answer:
First option: 30 miles per hour
Explanation:
For the first scenario, we will convert the minutes into hours first to get all the quantities in same unit
So,
20 minutes = 1/3 hours = 0.33 hours
Now using the speed, distance and time formula
Speed = distance/time




So the distance is 15 miles.
For returning through the same route
Time = 30 minutes = 0.5 hour
Distance = 15 miles
So,


Speed = 30 miles per hour
So first option is correct..