## Welcome to BrainDen.com - Brain Teasers Forum

 Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account. As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends. Of course, you can also enjoy our collection of amazing optical illusions and cool math games. If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top. If you have a website, we would appreciate a little link to BrainDen. Thanks and enjoy the Den :-)
Guest Message by DevFuse

# Number picking I. Even or odd?

Best Answer phil1882, 01 June 2014 - 06:01 PM

Spoiler for i mean...
Go to the full post

5 replies to this topic

### #1 bonanova

bonanova

bonanova

• Moderator
• 6148 posts
• Gender:Male
• Location:New York

Posted 31 May 2014 - 06:04 PM

You play a betting game with a friend.

You each place \$1 on the table. A computer then prints a random string of digits, from 0 to 9.

Players take turns erasing a digit from either end of the string and adding that number to their score.

When the last digit has been erased, the player with the higher score wins the \$2.

Players take turns moving first and choosing whether an odd or even number of digits are printed.

You're moving first on the next game. Which do you choose: even or odd?

• 0

Vidi vici veni.

### #2 phil1882

phil1882

Senior Member

• Members
• 562 posts

Posted 31 May 2014 - 09:54 PM

Spoiler for pretty sure..

• 0

### #3 phil1882

phil1882

Senior Member

• Members
• 562 posts

Posted 31 May 2014 - 10:31 PM

opps...

Spoiler for correction

• 0

### #4 bonanova

bonanova

bonanova

• Moderator
• 6148 posts
• Gender:Male
• Location:New York

Posted 01 June 2014 - 05:58 AM

opps...

Spoiler for correction

Are you sure this is best?

I'm assuming that "implement the sum" means "take (erase) the larger" of the two available numbers.

Might that not expose a much larger number for your opponent's next turn?

But maybe I misunderstood.

The reasoning in your first post is on the right track.

• 0

Vidi vici veni.

### #5 phil1882

phil1882

Senior Member

• Members
• 562 posts

Posted 01 June 2014 - 06:01 PM   Best Answer

Spoiler for i mean...

• 1

### #6 bonanova

bonanova

bonanova

• Moderator
• 6148 posts
• Gender:Male
• Location:New York

Posted 02 June 2014 - 02:51 AM

If you play first and you choose to have an even number of numbers, you can erase all the even numbers or all the odd numbers, whichever is larger, thus guaranteeing you will not lose. Worst case is if the even and odd sums are equal. Your approach seems better, I think, possibly guaranteeing a win in every case.

• 0

Vidi vici veni.

#### 0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users