All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Logic
The Best Strategy (Posted on 2003-03-18) Difficulty: 5 of 5
A box is filled with 'N' slips of paper. On each slip of paper is written some positive integer (note that any positive integer may appear on the slips - not just the integers from 1 to 'N'). The integers do not necessarily appear in any sequence or pattern. Each of the slips has a different integer on it, so there is just one slip with the greatest integer.

A person who has no prior knowledge of which numbers appear on the slips - but who does know that there are 'N' slips - is to blindly pull slips from the box one by one. The person looks at each slip, then either agrees to accept that number (of Rupees) and quit or decides to go on and choose another slip.

Note that the person looks at each slip as he/she proceeds, and then decides whether to quit or to go on. That person can go forward, but cannot go back. If no choice is made by the time the 'N'th slip is reached, then the person must accept the number (of Rupees) on the 'N'th slip.

Does there " EXIST " a 'Best Strategy' for the person ? If " YES ", then what is that strategy ? (Here the term " Best Strategy" means that the person will get the greatest amount of Rupees).

See The Solution Submitted by Ravi Raja    
Rating: 4.1818 (11 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re(3): regarding posted solution | Comment 37 of 47 |
(In reply to re(2): regarding posted solution by Cory Taylor)

As you have mentioned Cory in your comment that as events pass the probabilities change and that is what I have shown in my proof giving the formula for the probability of the occurrence of the highest number in a slip whose position is greater than 'k' depends on 'k' thus showing that the probabilities change, but as mentioned in the solution, that each of the first (i – 1) slips is equally likely to be the one with the highest number on them.
Then we obtain that: P{W | B(i)} = {k/(i – 1)}, if i is greater than k.
Also, we have the following results:
P(W) = (k/N)[{Summation from i = (k+1),(k+2),….,N}1/(i – 1)]
or, P(W) = (k/N)[{Summation from j = k,(k+1),(k+2),….,(N – 1)} (1/j)]


  Posted by Ravi Raja on 2003-03-26 20:23:08

Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (3)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information