Probability Questions Help

[implosion]

We got a bunch of questions to do for homework and there are two questions that I would appreciate some help with.

1) Suppose we deal five cards from an ordinary 52 card deck. what is the conditional probability that the hand contains no pairs, given that it contains no spades?

and this next question has two parts to it

2) Suppose we roll a fair six sided die and then pick a number of cards from a well-shuffled deck equal to the number showing on the die.

a)what is the probability that the number of jacks in our hands equals 2 ?
b) conditional on knowing that the number of jacks in our hand equals 2, what is the conditional probability that the die showed the number 3?

Thanks.

[yoursecretninja]

At exactly what stage in formulating a solution are you having a problem? How did you try to solve this problem? What did or did not work? We can't do your homework for you, but if you need help understanding something, than perhaps someone can help... but you'll have to more specific about where you need help... not just posting a homework question and expecting a solution.

[Brightguy]

1) Is just using the definition of conditional probability: P(A|B) = P(A&B)/P(B)
2a) Split into cases {die=1, die=2, ..., die=6} and use the law of total probability.
2b) Application of Bayes' theorem.