- #1
denian
- 641
- 0
i don't even have any idea how to start. please gives some hint.
each Supabrek packet contains a card from a set of n picture cards. A packet selected at random has the same prob. of containing anyone of the n cards.
The Smith family already possesses k ( < n ) different picture cards. They purchase a few more packets, selected one by one randomly until they find a card that is different from the k cards they already have. If this happens when they bought R packets, show that
P ( R = r ) = { (n-k)/(n) } { (k/n)^(r-1) }
thanks.
each Supabrek packet contains a card from a set of n picture cards. A packet selected at random has the same prob. of containing anyone of the n cards.
The Smith family already possesses k ( < n ) different picture cards. They purchase a few more packets, selected one by one randomly until they find a card that is different from the k cards they already have. If this happens when they bought R packets, show that
P ( R = r ) = { (n-k)/(n) } { (k/n)^(r-1) }
thanks.