Answer:
B) 4 hours
Explanation:
the equation relating speed , distance and time is as follows
speed = distance / time taken
the van moves 50 miles at 20 mph and the next 84 miles at 56 mph
so lets calculate the time taken at both speeds
substituting the values in the above equation
20 mph = 50 miles / time
time taken = 50 / 20 = 2.5 hours
56 mph = 84 miles / time
time taken = 1.5 hours
the totat time taken is - 2.5 + 1.5 = 4 hours
