Answer to 3 unit trial (1 Viewer)

[Jaserius]

Anybody know the answer to question 5a of the catholic trial this year?

Id really appreciate it.

Thanks.

 

[Jago]

It'd help if you could type upthe question for those of us who didn't do CSSA.

 

[Trev]

P(even) = 4/9; P(odd) = 5/9
i) 3C2*(4/9*3/8*5/7) = 5/14
ii) P(2 even 1 odd) = 3C2*(4/9)²(5/9) = 80/243

 

[rnitya_25]

The question is:

A bag contains 9 balls labelled 1,2,3,.....,9 but otherwise identical. Three balls are chosen at random from the bag. Find the probability that exactly two even numbered balls are chosen:

(i)if the balls are selected without replacement.
(ii)if each ball is replaced before the next is selected.

and trev's answers are perfect..