Expected number of cards you should turn before finding an ace
This is only an answer to your first question. I will show that your answer is correct by deriving the same answer in another way.
The probability that the seven of clubs turns up before the first ace is $\frac15.$ This is because each of the five relevant cards (the four aces and the seven of clubs) has the same one-in-five chance of being first.
Likewise, the probability that the jack of diamonds turns up before the first ace is $\frac15,$ and the same goes for the queen of hearts, the four of spades, and every other non-ace card in the deck. Since there are $48$ non-ace cards, the average number of (non-ace) cards preceding the first ace is $48\cdot\frac15.$
Imagine you have the following setup:
_A1_A2_A3_A4_
Each ace separated out evenly and we are interested in the pile that's before A1. For a standard deck of cards you have 52 cards - 4 aces = 48 cards left, and $$ \frac {48} 5 = 9.6$$ cards for each pile. So basically you would have to turn all 9.6 cards + the A1 card in order to see the first ace. So the answer is $$1 + \frac{48} {5} = 10.6 $$
Another way to do this with sums:
Suppose we draw all the cards in the deck. Let $k$ denote the place at which the first Ace appears. Note that $k$ can take integer values from $1 - 49$, because there must be at least $3$ other open spots for the other three Aces that will be drawn. We count the number of deals where the first Ace is in the $k^{th}$ spot as follows:
- If we fix the first Ace is at the $k^{th}$ spot in the deal, then the other $3$ Aces must occur after the $k^{th}$ spot in the deal. This means there are $52 - k$ spots these Aces can occur, and thus $\binom{52 - k}{3}$ places orderings for this aces in the deal IGNORING suit.
- To take in account suit, we multiply by $4!$ to account for all the permutations of the four suits of the aces.
- Now that we accounted for the aces, we just need to consider all the other 48 cards left. For each ordering of the aces, there are $48!$ different ordering of the other cards in the remaining $48$ slots of the deal. We multiply again by $48!$ to account for this.
- With that information, we know that since there are $52!$ total deals of the cards, meaning that the probability of getting the configuration with the first ace in the $k^{th}$ slot of the deal is: $\frac{\binom{52 - k}{3} \times 4! \times 48!}{52!}$
- Since expectation is just the sum $\sum{n * Prob(n)}$ where $n$ is just the number of cards until we draw the first Ace (including the Ace), we can just take the sum $\sum_{n = 1}^{49}{n \times \frac{\binom{52 - k}{3} \times 4! \times 48!}{52!}} = \frac{1}{52*51*50*49}\sum_{n = 1}^{49}{\frac{n \times 4! \times (52 - n)!}{3! \times (49-n)!}} = \frac{1}{52*51*50*49}\sum_{n = 1}^{49}{4 \times n \times (52 - n)(51 - n)(50 - n)} = 10.6$