help (1 Viewer)

[Arithela]

http://www.boardofstudies.nsw.edu.au/hsc_exams/exam-papers-2007/pdf_doc/maths-07.pdf

Question 9(b)i

can someone explain the reasoning behind P = 52/53 x 39/51

 

[Azreil]

http://www.boardofstudies.nsw.edu.au/hsc_exams/exam-papers-2007/pdf_doc/maths-07.pdf

Question 9(b)i

can someone explain the reasoning behind P = 52/53 x 39/51

Um.

P(different suits) = 1 * 39/51

1 because it doesn't matter what card you draw first.
39 because whatever card you draw first, there are 3 suits it's not, and those make up 39 cards.
51 because there are 51 cards left in a deck when 1 is withdrawn without replacement.

 

[Arithela]

sorry i still dont get the '52/53' part (from maths success one book)

 

[Azreil]

I have no idea why the book says it's 52/53, I'm sure it should be 52/52. There are only 52 cards in a deck...

 

[Arithela]

ah ok that makes sense then, ty

 

[adrian597]

what if there was a joker in the deck

 

[veloc1ty]

If it included jokers it would be 54. There's two of them.