I need help with these questions

Which coefficient matrix represents a system of linear equations that has a unique solution ? options in photo*

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

Wow i want to vacation in mexico jeremih wow old vacation in mexico jeremiah we read read reads a distance marker that indicates he is 89 km from juarez if 1 mile approximately 1.61 km how far is jeremiah from juarez