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

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J.B. Wood

Posts: 46
Registered: 8/29/06
Quick Solution to Puzzle?
Posted: Aug 7, 2013 8:12 AM
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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:

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