Question
How would you find the probability of drawing a face card and a 4 out of a standard deck of 52 cards? I got 4/13 but I don't think its right.
Answers
Anonymous
there are 13 numbers, and 3 of them are face cards. So, 3/13 would be the answer. Maybe you counted aces as face cards.
Ms. Sue
Anonymous -- I think you forgot the 4.
Jane
Theres 12 face cards (4 queens, 4 kings, and 4 jacks) and 4 fours. What would you do with 12/52 and 4/52?
Anonymous
oops. Guess I didn't read it right. Good catch.
Jane
Do I add them and that's it or do I do something else?
Reiny
Jane, from your wording it is not clear if the first card drawn is returned to the deck or not.
Suppose it is not returned
could be F4 or 4F
= (12/52)(4/40) + (4/52)(12/40)
= 3/130 + 3/130
= 3/65
Your answer suggests that the card is returned after it is drawn.
Then it would be (12/52)(4/52) = 3/169 for the F4
but it could have been 4F, for another 3/169
so the prob when the card is returned = 3/169+3/169 = 6/169
Suppose it is not returned
could be F4 or 4F
= (12/52)(4/40) + (4/52)(12/40)
= 3/130 + 3/130
= 3/65
Your answer suggests that the card is returned after it is drawn.
Then it would be (12/52)(4/52) = 3/169 for the F4
but it could have been 4F, for another 3/169
so the prob when the card is returned = 3/169+3/169 = 6/169