## Monday, June 29, 2009

### Train Schedule

Two friends are traveling on a train from NY to Boston. One of the friends says "It seems that the Boston-NY trains pass us every 30 mins. How many Boston trains do you think arrive in NY every hour?"

Kalonni said...

2? Since they pass them every 30 minutes and there are 60 minutes in an hour...

Maria said...

Nope. There is a trick...

Kalonni said...

No Boston trains will arrive in New York. All Boston trains will arrive in Boston.

Kalonni said...

I take back my last answer...

My family has determined that it should be 3.

ie: 9:00, 9:30, 10:00...

Maria said...

This is so cool that your whole family is participating. Try simulating the trains if you have enough people. The answer is still hiding. One of the previous puzzles - Atlantic Journey - may give a hint.

Kalonni said...

Ok, the new consensus is 1. This is because if they are passing them every 30 minutes, it would take at least another 30 minutes to reach the destination.

Barry said...

Hi Math Mom, I would also say 1. If the two friends' train weren't moving, then the answer would be 2, but since their train is moving away from NY, then the trains they pass are spaced apart by more than 1/2 hour.

Maria said...

You are both right - one train is arriving to NY from Boston every hour. Kalonni was first to come up with the correct answer, and Barry provided the correct explanation. I think you both deserve a point.
Kalonni - please email me your snail mail address to maria at marialando dot com and I will send you a prize.
Barry - welcome to the Marathon. 2 more miles (ooops, puzzles) to a prize.