Though this is not a competition site, congratulations to Lisa (the first) and to the others who achieve the correct solution, even without showing their reasoning.
Let's start trying to deduce what card is in the "house" 6.
1) Suppose card number 6 were an Ace.
Then, neither cards number 7 nor 8 could be an Ace (from (f)), could be a Queen (from (e)), and could be a King (from (c)). Then, at most one card of cards number 7 and 8 must be a Jack, wich contradicts (d). So, card number 6 is not an Ace.
2) Suppose card number 6 were a Queen.
Then, none of cards number 4, 5, 7 and 8 could be a Queen (from (f)), and could be an Ace (from (e)). Then, two Aces and a Queen would be cards number 1, 2, and 3, wich, from (e) and (f), is impossible. So, card number 6 is not a Queen.
3) Suppose card number 6 were a Jack.
Then, neither cards number 7 nor 8 could be an Ace (from (b)), could be a Jack (from (f)), and could be a King (from (c)). Then, at most one card of cards number 7 and 8 must be a Queen, wich contradicts (c). So, card number 6 is not a Jack.
Then, card number 6 is a King.
Since card number 6 is a King, card number 5 or 4 is a Queen, from (c) and (d).
If card number 5 is a Queen, then, from (d), card number 3 is a Jack. Then, from (c), card number 2 is not a Queen, and card numbers 1 and 4 are a King and a Queen, respectively. Then, card number 2 must be a Jack, wich contradicts (f). So, card number 5 is not a Queen, and therefore card number 4 is a Queen.
Then : from (f), neither of cards number 1 and 3 is a Queen; from (d), neither of the cards number 7 and 8 is a Queen; and card number 5 is not a Queen, as showed above. So, card number 2 is a Queen, and : from (d), card number 3 is a Jack; from (c), card number 1 is a King; and from (f), card number 5 is an Ace.
A Jack and an Ace are left for cards number 7 and 8, and you are not able to deduce what card is in these cells, because both options fits.
+---+
| K |
+---+---+---+
| Q | J | Q |
+---+---+---+---+
| A | K | ? |
+---+---+---+
| ? |
+---+ The two "?", one is an Ace and the other is a Jack (both option fits). |
