Answer:
A.) Time = 0.625 hrs = 37.5 minutes
B.) Speed required = 133.33km/hr
Explanation:
Given the following :
Total race distance = 100km
Total time required = 1 hour = 60 minutes
Average speed after traveling 50km = 80km/hr
80km/hr : This means it will take one hour to cover a distance of 80km
Therefore, time taken to cove first 50km at that average speed equals :
1 hour = 80 km
t hours = 50km
80t = 50
t = 50/80
t = 5/8 hours
t = 0.625hours
t = 0.625 * 60 = 37.5minutes
B)
Average speed required to complete the race in 1 hour = 100km/hr
Time used to complete first 50km = 0.625 hour
Time remaining: (1 - 0.625) hour = 0.375
Speed required = Distance left / time left
Speed required = 50 / 0.375
Speed required = 133.33km/hr
