12 September 2013

Puzzle – GPS

Headed to Raleigh. My flight back is tomorrow at a very early hour. So, I am going to send the puzzle today…
Remember the rules – message me on Facebook with your answer. Do not write on the comments section so as to give others a chance to solve it without peeking into possibly right answers.
This happened to me on Tuesday night. I was coming back from a customer dinner at night headed home. I never use the car GPS since I know I know my way around in Atlanta. However, midway thru my drive back, I noticed something interesting on the GPS.
The display on “Distance left to Destination” would count down as you would expect every mile but ever so often, it would jump up to a higher number. So it would read 16… then go down to 15 … then go down to 14 … and then jump to 20!!! It would again start counting down for a few miles and then jump up again!!!
Can you explain what was happening?
Here is a hint: Every time it would jump back up to a higher number, it would jump to a number higher than the previous high number.

Posted September 12, 2013 by Rajib Roy in category "Puzzles


  1. By Amitesh Mukherjee (Post author) on

    I think GPS was fine. You had a fun dinner, were in a good mood and was in no hurry to go home and were going in circles :-), probably listening to some good music. OR, you need a new car.

  2. By Murali Hegde (Post author) on

    I think number of times GPS jumped to a higher number is directly proportional to number of glasses of wine you had which is directly proportional to number of times you lost your direction which is indirectly proportional to your confidence on your own directional sense, hence the GPS numbers were going up and down!!

  3. By Anamika Chatterjee (Post author) on

    Why was there a destination if you were not even using the GPS? In mine it just shows current location when no destination is entered and I assume that’s how it usually works.

  4. By Bijetri Chakraborty (Post author) on

    Uncle, we don’t know what is GPS,except it found in a car, bus. So plz….. give another puzzle which we can try to solve. Though our 1st term is going on but mom never says anything if we solve your puzzles.

  5. By Rajib Roy (Post author) on

    Looks like we had some really innovative answers. If I ignore the strong hints that some of you laid around how much I must have drunk before or that the GPS was messed up (worse, from Microsoft πŸ˜‰ ), the logical and funny was Amitesh’s suggestion that I was going around in circles.
    Before I give the answer – which Bob got also – let me answer Anamika’s question. It is somewhat relevant to the answer. Her question was if I was not using GPS, why was there a destination punched in to begin with. Very legitimate question. Most GPS would not do it. However, the GPS on a Lexus (at least 2007 SC 430 anyways) remembers the last destination you had punched and starts every trip assuming you want to go there. (This can be easily reset).
    However, the puzzle still holds in other situations – like if you go beyond your desired destination without listening to your GPS instructions.
    Okay, now for the answer…

  6. By Rajib Roy (Post author) on

    The answer is that I was on a highway and the GPS was taking me to a place BEHIND me (because of the old default destination as explained previously; could have happened if I had crossed my home too). With every minute, I was going away from the GPS destination not towards it.
    The GPS was calculating the total distance as the distance from where I was to the nearest forward exits, adding the distance to take a U turn back to the highway and then the distance from that exit to the destination. With every mile that I was getting closer to the exit, the mile counter kept going down.
    But of course, I was paying no attention to the GPS. I simply kept going. When I crossed the exit that the GPS was telling me to take, it had to recalculate the total distance again – except, now it was assuming that I will take the NEXT exit and then a U turn. That explains the jump I was seeing, That would happen every time I skipped an Exit!!


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