...I figured the next step would be to determine which of Spott's 2 suits was the common one with Duce and how many cards of that suit each player held.
I still can't see how that can be determined without some if/then.
Jema, I think the suits can be logically determined:
Duce and Trey = clubs
- has to be clubs or spades (Trey only has black cards)
- ALL spades are held by Duce and Trey (Spott and Nave have none)
- only way they can have same number is 6 1/2 each
- so has to be clubs
Duce and Spott = diamonds
- has to be diamonds or clubs (Spott has only diamonds and clubs)
- if clubs, then Duce, Trey and Spott will have the same number
- we know that Nave has no clubs
- so only way Duce/Trey/Spott can have same number is 4 1/3 each
- so has to be diamonds
On the number of diamonds being 6:
- only 6 works, as you say
- then the number of clubs held by Duce/Trey are "logically" 3 (as you say)
- so this appears to require some "if/but" (must try 2 to 5 before!)
I'm still trying to find "something logical"...