Answer:
d = 576
Step-by-step explanation
Think of the two different speeds as belonging to 2 different cars going to the same place, taking the same route and going to the same place.
Let the time traveled by the fast car = t
Let the time traveled by the slower car = t+4
Let the rate of travel of the slow car = 36 mph
Let the rate of travel of the fast car = 48 mph
===========
d = 36*(t + 4)
d = 48 * t
Since the distance is the same, they can be equated.
48t = 36(t + 4) Remove the brackets.
48t = 36t + 144 Subtract 36t from both sides.
48t - 36t = 144 Combine
12t = 144 Divide by 12
t = 144/12
t = 12
Therefore the faster car takes 12 hours to get where it is going.
d = 48 * t
d = 48 * 12
d = 576