Question

Bus A and Bus B leave the bus depot at 2 pm.

Bus A takes 15 minutes to do its route and bus B takes 25 minutes to complete its route.
At what time are they both back at the bus depot together?
Give your answer as a 12-hour clock time.​

Answer 1

9514 1404 393

Answer:

3:15 pm

Explanation:

The least common multiple of 15 minutes and 25 minutes is 75 minutes. 75 minutes is 1 hour and 15 minutes. That amount of time after 2 pm is ...

3:15 pm

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Comment on least common multiple

The least common multiple of 15 and 25 can be found a couple of ways. One is by factoring:

15 = 3·5

25 = 5·5

then the LCM is 3·5·5 = 75.

Another way to find the LCM is by dividing the product by the greatest common factor: 15·25/GCF(15, 25) = 15·25/5 = 75.