In order to get the speed in km/h, we must divide the km by the h! So, we do 1689/3 to get 563, 913/2 to get 456.5, and 2556/4 to get 639. Now we see that San Francisco has the highest average speed.
Take the distance to travel and divide that by the hours it will take to make the full trip there. Your answer will be how far the plane travels per hour. San Fransisco travels farther per hour.
