Deck of cards.?

Question

30 cards from a deck of 52 playing cards and in a pile on a table. what is the difference between the number of black cards in this pile and the number of red cards in the rest of the deck?

Answer 1

well since there are 22 cards left, you can assume that 11 are red, because the probability of a card being red in the deck is 1/2. so you can also assume that the number of black cards in the pile of 30 is 15, because 30 * .5 =15. so the difference between them, most likely, is 15-11 or 4.

Answer 2

There are 26 black cards in the full deck. Let b be the number of black cards in the pile of 30. Then there are 26 - b black cards in the rest of the deck. Since there are 22 cards in the rest of the deck then there are 22 - (26 - b) = b - 4 red cards in the rest of the deck. The difference between the number of black cards in the pile of 30 and the number of red cards in the rest of the deck is b - (b -4) = 4.

Answer 3

It should be 4. You can easily see this by trying two different scenarios:

1. all 26 black cards are in the 30 card pile. Then the other pile has 22 reds, and 26 - 22 = 4

2. The 30 card pile has say 10 black and 20 red.The other has 16 black and 6 red. 10 - 6 = 4

Answer 4

B1 + R1 = 30

B1 + B2 = 26
R1 + R2 = 26

R1 = 26 - R2
B1 + 26 - R2 = 30
B1 - R2 = 4 So the difference will always be 4