Round fuis number 5,731 to the nearest 100

There are 45 questions on your math exam. you answered 810 of them correctly. how many questions did you answer correctly?

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?

The sum of the abscissa and the ordinate is six