## 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

# Calling all positive integers ...

5 replies to this topic

### #1 bonanova

bonanova

bonanova

• Moderator
• 6153 posts
• Gender:Male
• Location:New York

Posted 06 May 2013 - 05:20 AM

OK maybe not all.

How many pairs of mutually prime positive integers sum to 2x10250?

You should be able to do this on the back of an envelope, and probably can't count the pairs with a simple program (before the earth freezes.)

Pairs differing only in the order of addition count as 1 pair, not as 2 different pairs.
• 0

Vidi vici veni.

### #2 witzar

witzar

• Members
• 233 posts

Posted 06 May 2013 - 09:07 AM   Best Answer

Spoiler for

• 0

### #3 superprismatic

superprismatic

Not just Prismatic

• Moderator
• 1281 posts
• Gender:Male

Posted 06 May 2013 - 08:54 PM

Spoiler for I get

• 0

### #4 dark_magician_92

dark_magician_92

• Members
• 382 posts

Posted 06 May 2013 - 09:42 PM

Agree with Superprismatic. I think u have counted (1, 2*10^250-1) also.

• 0

### #5 bonanova

bonanova

bonanova

• Moderator
• 6153 posts
• Gender:Male
• Location:New York

Posted 07 May 2013 - 03:26 AM

Spoiler for I get

Spoiler for consider

• 0

Vidi vici veni.

### #6 superprismatic

superprismatic

Not just Prismatic

• Moderator
• 1281 posts
• Gender:Male

Posted 07 May 2013 - 02:55 PM

Spoiler for I get

Spoiler for consider

It seems rather difficult to pull the wool over the Denizens!

• 0

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

0 members, 0 guests, 0 anonymous users