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Sum Square Grid Row & Column ≠ 0 (Posted on 2010-04-29) Difficulty: 3 of 5
Each cell of a 1997x1997 square grid contains either +1 or -1, with no cell being vacant.

The product of all the numbers in the ith row, and the product of all the numbers in the ith column are respectively denoted by Ri and Ci.

               1997
Prove that  Σi=1(Ri + Ci) is always nonzero.

No Solution Yet Submitted by K Sengupta    
Rating: 2.0000 (2 votes)

Comments: ( You must be logged in to post comments.)
  Subject Author Date
re(2): Solution - (MS Word Formatting!?)Charlie2010-04-30 02:17:37
Solutionre(2): a simple proof NOW FOR THE PRODUCTAdy TZIDON2010-04-29 17:25:25
re: a simple proofDaniel2010-04-29 15:29:54
a simple proofAdy TZIDON2010-04-29 12:31:12
re: Solution - (MS Word Formatting!?)farcear2010-04-29 12:23:46
SolutionSolutionfarcear2010-04-29 12:18:11
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