redeemed545 wrote:
A company runs 2 trains every 60 minutes to London Victoria and 4 trains every 60 minutes to London Charing Cross from Orpingdon railway station (in southeast London), both at equally spaced intervals. Assuming there are no disruptions and that it takes no time for passengers to board and depart each train, which of the following is true?
A) A train to London Victoria and a train to London Charing Cross will meet at the station every 30 minutes or not meet at all.
B) A train to London Victoria and a train to London Charing Cross will meet at the station every 15 minutes or not meet at all.
C) A train to London Victoria and a train to London Charing Cross will meet at the station every 30 minutes or 60 minutes.
D) A train to London Victoria and a train to London Charing Cross will meet at the station every 15 minutes or 60 minutes.
I selected C, but the correct answer is A. This was from PrepSwift (GregMat). I solved this relatively easy problem as 30 minutes, but I selected C thinking they would also meet every 60 minutes. Is there something I am missing?
If the 2 trains to London Victoria to leave at XX:11 and XX:41, and the 4 trains to London Charing Cross leave at XX:00, XX:15, XX:30 and XX:45, then the trains will never meet.
So, we can eliminate C and D.
If the 2 trains to London Victoria to leave at XX:15 and XX:45, and the 4 trains to London Charing Cross leave at XX:00, XX:15, XX:30 and XX:45, then the trains will meet every 30 minutes.
Answer: A