Idea: The simultaneous departure time is the least common multiple of10,8,5, plus the initial departure time of 5:50.

Solution: The least common multiple of10,8,5 is 40, that is, after 40 minutes, there will be a second simultaneous departure at 6:30.

(2): The station stops all vehicles at 9:30 pm. How many times do these three buses leave at the same time every day

Idea: How many times do you leave at the same time from 5: 50 pm to 9: 30 pm for 40 minutes * * (plus the first one at 5: 50 pm)?

Solution: 9: 30 pm = 21:3021:30-5: 50 =15 hours and 40 minutes =940 minutes.

940/40=23 times ... 20 minutes.

23+ 1=24 times

A: Send it 24 times at the same time.