Answer:
The car was moving approximately at a speed of 37.74 miles per hour.
Step-by-step explanation:
We are given the following in the question:
The stopping distance of a car is given by
[tex]d = 0.05r(r + 2)[/tex]
where d is the stopping distance in feet and r is speed of the car in miles per hour.
The stopping distance is 75 feet, we have to find the speed of the car,
Putting d = 75 in the equation, we get,
[tex]75 = 0.05r(r + 2)\\r^2 + 2r = 1500\\r^2 + 2r-1500 = 0\\\\r =\dfrac{-2\pm \sqrt{4-(4)(1)(-1500)}}{2}\\\\r\approx -39.74,37.74[/tex]
Thus, the car was moving approximately at a speed of 37.74 miles per hour.
