To shutup FinalFantasy!... (prob qu) (1 Viewer)

[currysauce]

Urn A contains 5 black and 3 white balls while urn B contains 2 black balls and 7 white balls. A person selects either of the urns at random and takes 2 balls without replacement.

By the use of a tree diagram determine the prob. that the balls selected are of the same colour.

 

[KFunk]

I'm thinking it's somethign like:

P(same colour) =
1/2 x 5/8 x 4/7
+ 1/2 x 3/8 x 2/7
+ 1/2 x 2/9 x 1/8
+ 1/2 x 7/9 x 6/8 = 271/504 (I believe... I always make calculator errors)




EDIT: Told you so. [Alternatively you could do this question by subtracting the probability of getting different coloured balls from one which is somewhat quicker to calculate, it's also how I discovered that my initial calculation was wrong ]

 

[FinalFantasy]

y do u refer to me?

 

[Trev]

He has a crush, you see.

 

[FinalFantasy]

lol
(blah blah blah(10 letters))