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The game of blackjack is played with a deck consisting...

by AAPL » Fri Dec 29, 2017 7:20 am
The game of blackjack is played with a deck consisting of 13 cards ( one of each of the numbers 2-10, one jack, one queen, one king and one of ace) in each of fours suits: clubs, diamonds, hearts, and spades.

In a game of blackjack, if your first card is spade, what are the odds that it is an ace?

A. 1/52
B. 1/26
C. 1/13
D. 1/4
E. 5/13

The OA is C.

I don't have clear this PS question, the correct answer should be option D, because there are 4 aces only. I appreciate if any expert explain it for me. Thank you so much.
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by DavidG@VeritasPrep » Sun Dec 31, 2017 3:48 am
AAPL wrote:The game of blackjack is played with a deck consisting of 13 cards ( one of each of the numbers 2-10, one jack, one queen, one king and one of ace) in each of fours suits: clubs, diamonds, hearts, and spades.

In a game of blackjack, if your first card is spade, what are the odds that it is an ace?

A. 1/52
B. 1/26
C. 1/13
D. 1/4
E. 5/13

The OA is C.

I don't have clear this PS question, the correct answer should be option D, because there are 4 aces only. I appreciate if any expert explain it for me. Thank you so much.
We know that first card is a spade. So imagine a deck consisting solely of this suit. There'd be 13 cards. 1 of them would be an ace. So the probability of selecting an ace, given that we've selected a spade, would be 1/13, or C

You may have inadvertently rewritten the question in your head. If the question had been "If the first card selected is an ace, what is the probability that this card is also a spade?" then the answer would have been 1/4. (Imagine a deck that consisted solely of aces. Now you've got a deck consisting of 4 cards, 1 of which is a spade.)
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by Scott@TargetTestPrep » Sun Aug 25, 2019 5:42 pm
AAPL wrote:The game of blackjack is played with a deck consisting of 13 cards ( one of each of the numbers 2-10, one jack, one queen, one king and one of ace) in each of fours suits: clubs, diamonds, hearts, and spades.

In a game of blackjack, if your first card is spade, what are the odds that it is an ace?

A. 1/52
B. 1/26
C. 1/13
D. 1/4
E. 5/13

The OA is C.

I don't have clear this PS question, the correct answer should be option D, because there are 4 aces only. I appreciate if any expert explain it for me. Thank you so much.
Since there are 13 spades and one of them is the ace of spades, the probability of getting an ace when a spade is selected is 1/13.

[Note: The question stem asks for odds, but the answer choices are expressed as probabilities.].

Answer:C

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by Brent@GMATPrepNow » Mon Aug 26, 2019 5:33 am
AAPL wrote:The game of blackjack is played with a deck consisting of 13 cards ( one of each of the numbers 2-10, one jack, one queen, one king and one of ace) in each of fours suits: clubs, diamonds, hearts, and spades.

In a game of blackjack, if your first card is spade, what are the odds that it is an ace?

A. 1/52
B. 1/26
C. 1/13
D. 1/4
E. 5/13
Once we know that the card is a spade, we know that it must me one of the following 13 cards:
Ace of spades
2 of spades
3 of spades
4 of spades
5 of spades
6 of spades
7 of spades
8 of spades
9 of spades
10 of spades
Jack of spades
Queen of spades
King of spades

Each of the 13 possibilities above is equally likely,
So, P(card is Ace of spades) = 1/13

Answer: C

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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