Date: Nov 27, 2012 4:21 PM
Author: Jussi Piitulainen
Subject: Re: Interesting trivia - anybody has a different answer than I keep getting - zero

Stone Bacchus writes:

> My daughter and I were solving a math trivia and I could not come up
> with any answer other than zero. Would be interesting to see if
> somebody has a different opinion. The problem follows:
>
> You are at the start of a 1000 mile road with 3000 gummybears and a
> donkey. At the end of the road is a supermarket. You want to find
> the greatest number of gummy bears you can sell. Unfortunately, your
> donkey has a disease and can only carry 1000 gummybears at 1 time.
> Also, the donkey must eat 1 gummybear per mile.
>
> - You can drop off gummybears anywhere on the road
> - You can't carry gummybears while walking
> - No loopholes
>
> Again, this was a math trivia question and I could not ask anybody for
> clarification about what some the caveats meant or what the "no
> loopholes" meant, therefore I got zero.


Take 900 bears on the donkey, walk it 300 miles and back, leaving 300
bears at that milepost. The donkey will have eaten 600 bears. You and
the donkey and 2100 bears are standing where you started.

Take 1000 bears, walk the 300 miles. The donkey will have eaten
another 300 bears and has room for the pile of 300 bears that are
waiting there. (Take them.)

The donkey is again carrying 1000 bears. Walk the remaining 700 miles.
You will have taken 300 bears to the market (and left 1100 behind).

Therefore, the answer is at least 300. Probably more, of course.

(I don't see how to get the donkey back, though.)