PROBABILITY doubt

[SoniaKapoor]

3 winning tickets are drawn from an urn of 100 tickets.What is the pobability of winning for a person who buys 4 tickets???



please help..thank u

[Amit Goyal]

Pr(Winning for a person who buys 4 tickets)
=  1 - Pr(None of the 4 tickets he bought wins the prize)
= 1 - C(96, 3)/C(100, 3) = 1 -  (94 x 95 x 96)/(98 x 99 x 100) = 0.116
 

[SoniaKapoor]

thanku Sir :-)

[L14]

hi, pls clarify. I presume there are 3 winning tickets among the 100. And the person is drawing 4 tickets. We have to find the probability that he has drawn a winning ticket. correct?

[duck]

Hi Ben10.. :)

Yes!

[tanudas]

Why is it c(96,3) and not c(97,3) ?

[Akshay Jain]

[tanudas]

Thank you very much akshay ! That was so helpful :)
I used the same method.

However i am afraid i still can't grasp why it is c(96,3) , the way sir solved it.