What is 17 /9 in as a whole mixed number simplest form and 34/5 while or mixed numbers and simplest form and 51/7 whole or mixed number simplest form

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?