Given :
Three trolley tours leave from the same stop at 9:00 am.
Tour A returns to the stop every 75 minutes, Tour B returns every 60 minutes, and Tour C returns every 40 minutes.
To Find :
In how many hours will all three tours return to the stop at the same time.
Solution :
We know, they will return to the stop at the same time is the L.C.M of three i.e 75, 60 and 40 minutes.
So, their L.C.M is :
L.C.M = 600 minutes.
Now, 600 minutes = 600÷60 hours = 10 hours.
Therefore, they will all meet at stop in 10 hours.
Hence, this is the required solution.