Math Is Fun Forum

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Deck of Cards

What is the probability of drawing a KING and then drawing a QUEEN from a regular deck of 52 cards?

Note: Here event A affects event B because of the rule of the game.

Kings in a deck = 4

Queens in a deck= 4

A = drawing a king

B = drawing a king

P(A) = 4/52 = 1/13

Do not place the selected king's card back into the deck, which means we now have 51 cards.

P(B) = 4/51

P(A and B) = P(A) • P(B)

P(A and B) = 1/13 • 4/51

P(A and B) = 4/153

You say?

Keep_Relentless

Member

From: Queensland, Australia

Registered: 2024-05-05

Posts: 61

Re: Deck of Cards

I get a much smaller number when multiplying 1/13 and 4/51.

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"The most incomprehensible thing about the world is that it is comprehensible." -Albert Einstein.

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Re: Deck of Cards

I get a much smaller number when multiplying 1/13 and 4/51.

Really? How can that be? I cannot move away from this topic just yet.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,627

Re: Deck of Cards

P(A and B) = 1/13 • 4/51

You are ok up to here. Try working out 13 x 51 again.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Re: Deck of Cards

P(A and B) = 1/13 • 4/51

You are ok up to here. Try working out 13 x 51 again.

Bob

The calculator tells me that 13 x 51 = 663.

I then get 4/663.