What does 1/2y+6++3/2y=2y-6y-30 equal

I’m stuck on this i don’t understand.

Solve the problem by making up an equation. a man could arrive on time for an appointment if he drove the car at 40 mph; however, since he left the house 15 minutes late, he drove the car at 50 mph and arrive 3 minutes early for the appointment. how far from his house was his appointment?

Ineed with question three. i don't understand how i'm supposed to achieve 3 marks.