Question

Commuter trains depart from North Station every 10 minutes, and subway trains depart every 3 minutes. If a subway train and a commuter train both leave the station at 8:15, how long will it be before the subway train and the commuter train depart again at the same time?

A) 15 minutes
B) 20 minutes
C) 25 minutes
D) 30 minutes

Answer 1

The subway train and the commuter train will depart at the same time again after 30 minutes.

Step-by-step explanation:

To answer this question, we need to find the least common multiple (LCM) of 3 and 10, which will give us the time it takes for both the subway train and the commuter train to depart at the same time again.

The LCM of 3 and 10 is 30, so it will take 30 minutes for the subway train and the commuter train to depart at the same time again.

Therefore, the correct answer is D) 30 minutes.