Explaining the influence of the arabian civilization on africa.

Antti entered a  -kilometer race. his goal is to finish in one hour. he starts off sprinting, and completes the first    kilometers of the race at an average speed of    kilometers per hour.to achieve his goal of a one-hour finish time, what average speed (in kilometers per hour) must antti maintain for the last    kilometers of the race? enter your answer as a number in decimal form, without units.hint(s):

the answer is b

Explanation: