Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.


Math Forum » Discussions » sci.math.* » sci.math

Topic: Quick Solution to Puzzle?
Replies: 12   Last Post: Aug 13, 2013 6:11 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
J.B. Wood

Posts: 45
Registered: 8/29/06
Quick Solution to Puzzle?
Posted: Aug 7, 2013 8:12 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Hello, all. I came across this puzzle in an old computer reference book
in a chapter dealing with efficient programming techniques:

Find a 7-digit phone number (I told you the book was old) such that when
the first three digits are subtracted from the last four and the result
squared you obtain the original 7-digit number. The answer is 1201216.
I'm uncertain if there are any other integer solutions. The problem
can be reduced to a quadratic in two unknowns and numbers substituted
until the answer is obtained. Does anyone know of an alternative,
relatively fast (pencil & paper) solution? Thanks for your time and
comment. Sincerely,
--
J. B. Wood e-mail: arl_123234@hotmail.com



Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.