Answer:
Average speed of Robbi = 16 mph
Step-by-step explanation:
Formula for the average speed is,
Average speed = [tex]\frac{\text{Total distance covered}}{\text{Total time taken}}[/tex]
Total distance covered by Robbi = 3 + 7 + 12
= 22 miles
Time taken to cover 3 miles = [tex]\frac{\text{Distance covered}}{\text{Speed}}[/tex]
= [tex]\frac{3}{8}[/tex] hours
= 0.375 hours
Time taken to cover 7 miles = [tex]\frac{7}{14}[/tex]
= 0.5 hours
Times taken to cover 12 miles = [tex]\frac{12}{24}[/tex]
= 0.5 hours
Total time taken to cover the entire trip = 0.375 + 0.5 + 0.5
= 1.375 hours
Average speed of Robbi = [tex]\frac{22}{1.375}[/tex]
= 16 miles per hour
