Answer:
the average speed of the car is 170 mph.
Explanation:
Given;
initial speed, u = 70 mph
time of motion, t₁ = 3 hours
final speed, v = 20 mph
time of motion, t₂ = 2 hours
The average speed of the car is calculated as;
[tex]v' = \frac{70(3) - 20(2)}{3-2} \\\\v' = 170 \ mph[/tex]
Therefore, the average speed of the car is 170 mph.