SOLUTION: I really need your help. Please and Thank you! Two shuttle buses pick up passengers in an airport parking lot. One bus departs every 15 minutes. The other bus departs every 25 m

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Question 1036244: I really need your help. Please and Thank you!
Two shuttle buses pick up passengers in an airport parking lot. One bus departs every 15 minutes. The other bus departs every 25 minutes. At the beginning of the day, both buses depart from the same terminal at the same time. How long will it be before they both depart at the same time again?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
It is the least common denominator for 15 and 25 minutes. Multiplying them together will give A common denominator of 375 minutes. It won't be longer than that.
The easiest way is to remember that the bus that departs every 25 minutes will leave 25,50,75,100... minutes.
One only needs to look for where 15 divides evening into those numbers, and it is 75 minutes.
One departs every x minutes and the other every 5x/3 minutes. Five departures of 1 will equal 3 departures of the other: 75 minutes.