Math Is Fun Forum

babyangel1972

Member

Registered: 2005-12-12

Posts: 18

Don't mean to be a bother,,just need help setting up :(

Not looking for the answer I am just horrible at math and don't understand.  Can you help me understand how to set up the problem.

a. Drawing from a regular deck of playing cards, what is the probability of drawing a face card (jack, queen, king) 3 times in a row?  (assume that jokers are taken our and assume no replacement)

b.  How would the probability change if you assumed replacement?

gnitsuk

Member

Registered: 2006-02-09

Posts: 121

Re: Don't mean to be a bother,,just need help setting up :(

At the moment when you pick the first card there are 52 cards in the deck of which 12 are face cards. So the chances of the first card being a face card is 12/52 (12 chances out of 52) which cancels down to 3/13.

Now the chances of picking another face card from the remaining pack compound with the previous answer to give a chance of drawing two face cards of:

3/13 * 11/51 (11 because there are now 11 face cards left and 51 because there are now only 51 cards left)

And so for three face cards = 3/13 * 11/51 * 10/50 = 330/33150 = 11/1105 =0.0099

For the second part, the chances are modified as you would expect to produce:

3/13 * 3/13 * 3/13 = 27/2197 = 0.0122

Last edited by gnitsuk (2006-07-10 20:39:31)