Answer:
B) 6 hours
Explanation:
Let h represent the total trip time. Then h/2 is the time spent traveling at each speed. The distance covered is ...
... distance = speed · time
The sum of the distances in each mode is the total distance.
... 1020 = 55·h/2 +285·h/2
... 2040 = h·(55+285) . . . . multiply by 2
... 2040/340 = h = 6 . . . . . . . divide by the coefficient of h
The trip took a total of 6 hours.