Simplify -13 - 4y - 5z + 15 - (-4z) + 11y

Ineed with math stuff it involves graphs

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

38 points and brainliest plz answer question in word document