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Another 2006 Problem (Posted on 2006-09-30) Difficulty: 2 of 5
Determine the total number of positive integer solutions of:

2/x + 3/y = 1/2006

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (1 votes)

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Solution | Comment 1 of 9

There are 72 positive integer solutions thato exist.

The equation 2/x + 3/y = 1/2006 can be rewritten as 2*2006/x + 3*2006/y = 1.

Since the equation 1/(n+1) + (n-1)/(n+1) = 1, using the factor value of 1; the prime factors of 2006: 2, 17, 59; and the primes 2 and 3 for each separate fraction of the original equation; and the composite numbers of the primes, one can find 27 of the positive integer solutions.  

Initially missed (as pointed out by K Sengupta in the following post), a 28th solution is available as the following equation: 2*n/(2+3)*n + 3*n/(2+3)*n also equals 1, where n<>0.

An additional 44 can be found using a little brute force where the x value is > 2006*2 and the y value < 2006*3.

The following are x, y values that will provide solutions where both x and y are positive.   
    4013 24150234
    4014 12078126
    4015  8054090
    4016  6042072
    4018  4030054
    4020  3024045
    4024  2018036
    4029  1426266
    4036  1012027
    4046   716142
    4063   479434
    4071   415242
    4080   361080
    4114   242726
    4130   210630
    4148   183549
    4189   142426
    4216   124372
    4248   108324
    4301    89562
    4366    74222
    4420    65195
    4484    57171
    4590    47790
    4720    40120
    4879    33866
    5015    30090
    5168    26904
    5428    23069
    5746    19942
    6018    18054
    6324    16461
    7021    14042
    7480    12980
    7493    12954
    8024    12036
   10030    10030
   10948     9499
   10974     9486
   12036     9027
   14455     8330
   16048     8024
   17936     7752
   21063     7434
   24898     7174
   28084     7021
   31860     6885
   38114     6726
   45784     6596
   55165     6490
   63189     6426
   72216     6372
   87556     6307
  106318     6254
  122366     6222
  140420     6195
  181543     6154
  208624     6136
  240720     6120
  359074     6086
  413236     6077
  477428     6069
  714136     6052
 1010021     6042
 1424260     6035
 2016030     6030
 3022039     6026
 4028048     6024
 6040066     6022
 8052084     6021
12076120     6020
24148228     6019

Edited on October 1, 2006, 9:22 am

Edited on October 2, 2006, 8:43 pm
  Posted by Dej Mar on 2006-09-30 07:53:54

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