There are 100 cards in a set. I have 98 of them. The cards are sold in packs of 7. I need 2 more to complete the set.

If i buy one pack what is the probability that the first card is one that i need?

I got 1/50.

Find the probability that i find neither of the cards i need in the 7 cards of the pack.

I got 43/50.

Let the event that I get a card that i need = C and the event that i dont Cdash. FInd the probability that i get exactly one card that i need. (edit: in the 7 cards if one pack)

I am stuck...

Thanks!