Min has a shelf filled with books. The books have different thicknesses. This line plot shows the thickness of each book. He piles the four thickest books on top of each other. How thick is the pile?

Randy and trey take turns cleaning offices on the weekends. it takes randy at most 4 hours to clean the offices. it takes trey at most 6 hours to clean the offices. what is the greatest amount of time it would take them to clean the offices together? 2.4 hours 2.5 hours