Help quickly as possible please :)

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

Which rule describes the composition of transformations that maps △abc to △a”b”c

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