Answer: 64.8 mph
Step-by-step explanation:
Given
Arriving time is 6 hours
return time is 4 hours
The average speed of returning 81 mph
Distance traveled while returning

the average speed of the entire trip is

Answer: 520
Explanation: The 4 is not bigger than 5
C = pi * d
Plug in what we know:
C = 3.14 * 26
Multiply:
C = 81.64