Assuming that you are only using one deck, and there are only four cards on the table. If you have a 10 and a 7 showing, the dealer has a 10 showing, calculate the probability of the dealer's other card being an 8, 9, or a face card.

Also, explain why it makes sense to hit on a 16 but to stand on a 17. If the house will stand on a 17 and above, how would you justify this strategy?