ROW  +--+--+--+--+
     |A |B |C |D |       
1    |  |  |  |  |       
     +--+--+--+--+
     +--+--+--+--+
     |H |G |A |C |      
2    |  |  |  |  |       
     +--+--+--+--+
     +--+--+--+--+
     |E |F |G |H |       
3    |  |  |  |  |      
     +--+--+--+--+

1. Row 1 has four cards with different letters on each of the two sides.
2. Row 2 has the same four cards from Row 1, two of which have been turned over and, all four of which are in different positions.
3. Row 3 has the same four cards from Row 2, two of which have been turned over and, all four of which are in different positions relative to the positions they were in Row 1 and Row 2.

Which letter is on the other side of each of the four cards in row 3?

In order: C-A-D-B.

In row 2 the first two cards must be the reverses of B&D.  Since the B can't be the second card the B is first and D is second.  So we know the cards are BH and DG.

That leaves only the first two cards in the third row as the reversed of A&C. Since the A can't be on the first card, C is the first and A is the second.  These cards are then CE and AF.

Posted by Jer on 2013-09-20 10:15:33