Logic Puzzle!

Have been musing about various logic puzzles latelty and thought I would open one up to the audience, so here it goes!

The Bus Riddle:

You live 5 minutes away from a bus stop, the bus waits at the stop for 30 seconds every 10 minutes. You wake up early one morning and have no idea what time it is, but you are late for work!

If running is twice as fast as walking. What do you do?

Suggestions in blog comments! ^_^

Ian

Comments

• Anonymous
  March 16, 2006
  Phone work and tell them I'll be late
• Anonymous
  March 17, 2006
  Walk it to the stop, no point in running if you miss it you got longer to wait for the next bus.  
  
  
• Anonymous
  March 17, 2006
  work from home
• Anonymous
  March 17, 2006
  Run to the stop and wait here: this increase chances of getting on the nearest bus (in case it leaves stop in less than 5 min since you left home). However, you will have to wait more in all other cases.
• Anonymous
  March 17, 2006
  If you run, on average, you'll wait longer.
  Min       Walk            Run
  0 5 7.5
  1 4 6.5
  2 3 5.5
  3 2 4.5
  4 1 3.5
  5 0 2.5
  6 9 1.5
  7 8 0.5
  8 7 9.5
  9 6 8.5
  10 5 7.5
  
  4.5 5.2
  
• Anonymous
  March 17, 2006
  The comment has been removed
• Anonymous
  March 17, 2006
  The comment has been removed
• Anonymous
  March 17, 2006
  To SDL
  
  I like the solution but I am not sure it is complete.  The last part to consider is that the bus waits for 30 sec.  Look at the row min = 8.  You have 9.5 min wait however that should not be possible since the bus will wait for 30 sec.  That will change the average for running to less than 4.5 min.  Unless you live in Pittsburgh where the bus drivers floor it when they see you running up.
  
  0 5 7.5
  1 4 6.5
  2 3 5.5
  3 2 4.5
  4 1 3.5
  5 0 2.5
  6 9 1.5
  7 8 0.5
  8 7 0
  9 6 8.5
  
  4.5 4.05
  
  
• Anonymous
  March 17, 2006
  You don't state what the goal is.  You merely state the setup.
  
  If the goal is to get to work earlier, then obviously -- run.
  
  If the goal is to spend the least time waiting at the stop, and you don't care when you get to work as long as you arrive this same workday, then it's an open question:   if you have surveillance of the stop, then you can time it so that you arrive exactly with the bus.
  
• Anonymous
  March 21, 2006
  hehe :) well I face this problem pretty much every morning when I wake up. The idea is to catch the first bus possible.
  Great comments, we had a good debate in the office about it too :D
• Anonymous
  April 03, 2006
  If you wake up early one morning  how are you late?
• Anonymous
  April 04, 2006
  haha,
  
  Morning is always early :)
  
  Another point is that you don't know what time it is, so technically you can't be certain it is early or even if it is the morning but that is details! :)