Answer: C) 44 mph
Step-by-step explanation:
We know that [tex]\text{Time}=\dfrac{\text{Distance}}{\text{Speed}}[/tex]
Given : A car drives 40 miles on local roads at 20 mph.
i.e. Time taken : [tex]t_1=\dfrac{40}{20}=2\ hour[/tex]
Also, it drives 180 miles on the highway at 60 mph.
i.e. Time taken : [tex]t_2=\dfrac{180}{60}=3\ hour[/tex]
We know that the formula for Average speed is given by :-
[tex]A.V.=\dfrac{\text{Total distance}}{\text{Total Time}}[/tex]
So the average speed of the entire trip will be :-
[tex]\dfrac{40+180}{t_1+t_2}\\\\\\=\dfrac{220}{2+3}=\dfrac{220}{5}\\\\=44[/tex]
Hence, the average speed of the entire trip is 44 mph.
Therefore , the correct answer is C) 44 mph.
