Puzzle #15: The Early Commuter

A commuter is in the habit of arriving at his suburban station each evening at exactly five o’clock.  His wife always meets the train and drives him home.  One day he takes an earlier train and arrives at his station at four o’clock.  The weather is pleasant so instead of telephoning home, he starts walking along the route always taken by his wife.  They meet somewhere along the way. 

He gets into the car and they drive home arriving ten minutes earlier than they usually do.  Assuming that the wife always drives with a constant speed, and on this particular occasion she left just in time to meet the five o’clock train, can you determine how long the husband walked before he was picked up?

Source: My Best Mathematical and Logic Puzzles, by Martin Gardner; Puzzle #8

Target Ages: All ages

This entry was posted in Puzzles and tagged , , . Bookmark the permalink.

12 Responses to Puzzle #15: The Early Commuter

  1. Sunil Dhar says:

    55 min

  2. Anoop says:

    Hi Alok,
    Should be 55 minutes..

  3. Sairam says:

    Assuming the wife usually travels an hour daily, she must leave at 4.30 to pick her husband and both reach back home at 5.30. On this ocassion they returned home 10 mins early, i.e. at 5.20, which means the wife travelled for 50 mins both ways. That would mean the husband walked for 25 minutes.

  4. vikasvats says:

    One of my favorites. It begs for more data but yet has such a simple solution …

    • Alok Goyal says:

      Agreed. I tried this puzzle in February, and initially wandered around quite a bit and in the end realized that the solution was rather simple and felt very stupid!

      • Ruchi T says:

        i also was trying with some equations, then felt, for equations need more data … bt at times its one simple hint – which make it work! The constant speed did the trick for me…

  5. Ruchi T says:

    another good one…

  6. Viveksheel says:

    He walked for 1 hour and 5 minutes.

  7. vivsheel12 says:

    He walked for 1 hour and 5 mins.

  8. Rajeev Kumar says:

    5 minutes

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s