First, determine the distance of the motorcycle and the car from the start point. The distance could be determined using d stands for distance, v stands for speed, t stands for time
The car d = 48 × t d = 48t
The motorcycle d = 20 × t d = 20t
At the end of t hours, the car is 48t miles (east) from the start point and the motorcycle is 20t miles (north) from the start point.
Second, determine the distance between 48t miles at east and 20t miles at north using pythagoras distance = distance = distance = distance = 52t
The expression for their distance apart at the end of t hours is 52t