Step-by-step explanation:
In the first part, he was travelling with twice the speed, or Vs, for distance
48 - d, for 2 hours.
speed = distance/time
distance = speed * time
First part :
48 - d = 2V * 2
⇒d + 4V = 48
Second part:
d = V * 2
⇒d = 2V
Substitute 2s for d in equation 1.
2s + 4s = 48
6s = 48
s = 8
The speed in the second part is 8 mph.
The speed in the first part is 2s = 2(8) = 16
I hope this helps
