Answer:
30 miles/hour, and 2.24 miles/hour
Step-by-step explanation:
 
What is average speed?
It is the total distance traveled divided by the time taken to cover the total distance traveled
 
Given that the various distances are 
20 miles and 10 miles 
the total distance traveled is 20+10= 30 miles
the average speed is expressed as
average speed= total distance/time taken
average speed= 30/1
average speed= 30 miles/hour 
The average velocity is a vector quantity 
the velocity is the average displacement divided by time taken

average velocity= displacement / time
average velocity= 2.24 /1
average velocity= 2.24 miles/hour