Problem 2

Crossing The Desert

A traveler undertakes to walk, alone and without help, across a desert entirely lacking in resources. Every 20 kilometers on the 100 kilometer trail there is a shelter. (20 kilometers is exactly what a traveler can walk in one day.) The traveler can only carry 3 days' food. He can stock food only in shelters. How many days will it take him to cross the desert? — Mr. Simmons

Your Thoughts…

Subhash G: Oh yeah! I remember this problem!

But i won't say anything, mr. s! Dont worry!

Well, I'm confused. Does it really matter if he carries food or not? If the problem doesn't mention how long he can go without food, then I think it would still be five days right?

-Michelle L.

Oops, i misread the question…
Well, let me think about it.

-Michelle L.

Okay, I got it.
if the amount saved at the shelter is negative, then that means that food is taken out.
also, keep in mind that the traveler has to eat every trip he makes.
this is assuming that the problem is asking that he needs to eat every day and that all of his food is stored at the "starting point" as I labeled it.

Day Places Traveled Amount Saved At Shelter Total at that shelter On Hand Afterwards
1 starting point-shelter 1 1 1 1
2 shelter 1-starting point 0 infinite 3
3 starting point-shelter 1 1 2 1
4 shelter 1- starting point (yes, this is going to get somewhere) 0 infinite 3
5 starting point-shelter 1 -1 1 3
6 shelter 1-shelter 2 1 1 1
7 shelter 2-shelter 1 -1 0 1
8 shelter 1-starting point 0 infinite 3
9 starting point-shelter 1 1 1 1
10 shelter 1-starting point 0 infinite 3
11 starting point-shelter 1 -1 0 3
12 shelter 1-shelter 2 -1 0 3
13 shelter 2-shelter 3 0 0 2
14 shelter 3-shelter 4 0 0 1
15 shelter 4-shelter 5 (DONE!) 0 0 0

My final answer is 15.

-Michelle L.
P.S. If we get this right, I'm taking all the credit since NO ONE ELSE is helping me with this even though it's been here for like, 3 days.

… ouch. anyway. thats rather cold.
i didnt know it was up D:
it just said it was up on his webbie today.
also. it doesnt state how many packs of food at the starting point because "entirely lacking in resources"
therefore, he can't have started with food… and how does the starting point end up with "unlimited"?
its not like someone is going to be nice enough to drop "unlimited" amounts of food from where he started


It's been there for a long time -.-.
i know, but i told you, i'm assuming.
like he put his "camp" there, i guess. with all food and stuff.
because no offense, but the problem isn't written all that well…


wow…when did this get put up??? I had NO idea…..
~Ann K.

actually… dont answer that….
~Ann K.

may 4th XD

dont assume,
it makes a… well, you should be able to figure it out.

-Peter F.

okay peter.
then what is your "correct and unassuming answer"?

i dont get the question -.-
-Ryan D.

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