There are 5 DVDs. 2 of them contain videos, 3 - musics. 2 friends take them one by one ( that is A takes 1, B takes 1, A takes 1, B ...).
1) Find the probability that the first taken DVD contains videos.
2) Find the probability that the DVD with videos first time will be taken on first or second try. (If taken on first and second try, it doesn't count)
3) In how many ways 2 friends can share these DVDs if they take at least 1 ? ( All 5 have to be taken)
Hi, so I'm having some trouble with the 2nd task, although I'm not sure if I've got the others right.
1) This is 2 / 5 ?
2) So I was thinking about adding two possibilities : one when that DVD is taken on first try, and one when taken on second try.
First try : 2 / 5
Second try : (3 / 5) * (2 / 4) = 3 / 10.
3 / 5 is the chance to take music on first try, and 2 / 4 is the chance to take required DVDs on second try. Since one DVD is already removed, only 4 left to pick from.
(2 / 5) + (3 / 10) = 7 / 10
I'm guessing this is incorrect ?
3) 4 * 1 + 3 * 2 + 2 * 3 + 1 * 4 = 20
So friend A takes 4 and B takes 1, etc. Is this right ?
Thanks !
1) Find the probability that the first taken DVD contains videos.
2) Find the probability that the DVD with videos first time will be taken on first or second try. (If taken on first and second try, it doesn't count)
3) In how many ways 2 friends can share these DVDs if they take at least 1 ? ( All 5 have to be taken)
Hi, so I'm having some trouble with the 2nd task, although I'm not sure if I've got the others right.
1) This is 2 / 5 ?
2) So I was thinking about adding two possibilities : one when that DVD is taken on first try, and one when taken on second try.
First try : 2 / 5
Second try : (3 / 5) * (2 / 4) = 3 / 10.
3 / 5 is the chance to take music on first try, and 2 / 4 is the chance to take required DVDs on second try. Since one DVD is already removed, only 4 left to pick from.
(2 / 5) + (3 / 10) = 7 / 10
I'm guessing this is incorrect ?
3) 4 * 1 + 3 * 2 + 2 * 3 + 1 * 4 = 20
So friend A takes 4 and B takes 1, etc. Is this right ?
Thanks !