Question

Seven cards are dealt from a standard deck.
what is the probability that three of the seven are hearts?

Answer 1

P(3 hearts) = 13/52 + 12/51 + 11/50

I forget exactly how to do the rest, but I'm pretty sure you use C(7,52) * (P)^n * (P)^n-k

Answer 2

oh ok yy

Answer 3

ty

Answer 4

(1-P)^n-k that is

Answer 5

(1-P)^n-k that is

Answer 6

im not getting the right answer
what did u get?

Answer 7

im getting 0.70

Answer 8

from the 13 hearts you need 3, and then there's 39 other non heart cards, that you need 4 of. The total is the 7 from the 52, in the denominator.
\[\Large P = \frac{ 13 C 3 * 39 C 4}{ 52 C 7 }\]

Answer 9

oooh okaay i get it, thanks, btw r u a matrix fan?

Answer 10

haha, yes. Agent Smith.

Answer 11

how would you get the expected number of hearts?

Answer 12

Hmm idk at the moment. I'll think about it.

Answer 13

welcome to the 99 club

Answer 14

haha thanks, can't even see it cos OS isn't working.

Answer 15

so any one figure it out yet?

Answer 16

are u still doing the same question?

Answer 17

im not part b of it

Answer 18

what is the expected number of hearts

Answer 19

im getting 1.3

Answer 20

it should b 1.8

Answer 21

are you sure its not 1.75

Answer 22

im not getting that
what was your P value

Answer 23

no i mean should it be 1.8 exact or was it rounded from 1.75

Answer 24

i think the book rounded the answer to 1.8

Answer 25

ok well i just did 7 * 1/4

Answer 26

i dont think this is the right way tho

Answer 27

where did u get the 1/4?

Answer 28

well, 1/4th of the cards are hearts