Blackjack. A gambler playing blackjack in a casino using four decks noticed that 20% of th...

Blackjack. A gambler playing blackjack in a casino using four decks noticed that 20% of the cards that had been dealt were jacks, queens, kings, or aces. After x cards had been dealt, he knew that the likelihood that the next card dealt would be a jack, a queen, a king, or an ace was  For what values of x is this likelihood greater than 50%?