Andrew has six fewer coins than casey. bob has two more than twice as many coins as andrew. altogether, they have 504 coins. how many coins does bob have?

Andrew: x - 6
      Bob: 2x - 12
  Casey: x

  (x - 6) + (2x - 12) + x = 504
(x + 2x + x) + (-6 - 12) = 504
                        4x - 18 = 504
                            + 18   + 18
                               4x = 522
                                4       4
                                 x = 130.5

I’m not absolutely sure but i think it’s 7x6x5x4x3x2=5040 because as the first character you can take any of the 7 given then you are left with 5 then 6 then 4 etc.