You need to catch two different buses to get to the shops bus 1 is due to leave at 2 o'clock and arrive at 2.30. you have a half hour wail between getting off the first bus and getting on the second bus.
bus 2 is due to arrive at the shops at 3.15.
(a) what time is bus 2 scheduled to leave? bus 2 leaves 15 minutes early
(b) what time does it leave? () what time does it anive?
bus 1 is 15 minutes late.
(c) what time does it arrive?