If you dont know. use x as your original value. Therefore. you would have: x - 15 + 9 after the second stop you would have: (x - 15 + 9) - 4
So your answer would either be... There was ______ more people on the bus before 2:30 than there was after the second stop. There was ______ more people on the bus after the second stop than there was before 2:30.