Finally, if A could not now deduce his number then the additional arrangements would now not be possible (same logic again): (4n,3n,n), (3n,2n,n), (8n,3n,5n), (5n,2n,3n), (4n,n,3n), (3n,n,2n). But, since A can deduce his number, then one of these new situations is possible. Since A says 65 then the only arrangement where the first number is divisible by 5 must be the answer I.e. (5n,2n,3n) with n=13, and the numbers he sees are B 2*13=26 and C 3*13=39!!