Mrs. cail's class took a field trip to the zoo. the class was scheduled to leave the zoo at 2: 30 p. m. however, before they could leave, the bus driver noticed one of the tires on the bus was flat. it took the driver 50 minutes to change the flat tire. if the trip back to school was 25 minutes long, at what time should the students have arrived if the bus had not had a flat tire?