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Reciprocal Equation #1 (Posted on 2003-07-18) Difficulty: 2 of 5
Find all sets of integers A, B, and C which satisfy the following:

1/A + 1/B + 1/C = 1.

See The Solution Submitted by Brian Smith    
Rating: 3.2500 (4 votes)

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re: solution? | Comment 3 of 5 |
(In reply to solution? by Charlie)

Yes, that's the complete solution. It's pretty straightforward to prove.
Let's assume that we are not interested in permutations and define A<=B<=C.
Now, since 1/A, 1/B and 1/C have to be 1/3 on average, A (the smallest number of the solution) has to be either 2 or 3.
For A=3, {3, 3, 3} is obviously the only solution.
For A=2, 1/B and 1/C have to be 1/4 on average, so B has to be either 3 or 4 (2 obviously doesn't work), so {2, 3, 6} and {2, 4, 4} are the only remaining solutions.
  Posted by exoticorn on 2003-07-18 04:02:13

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