The probability that a student owns a dog is 1/3. The probability that the same student owns

a dog and a cat is 2/15. Determine the probability that the student owns a cat.

Let us call p the probability of occurence of the event D: "a student owns a dog"

and q the probability of occurence of the event C: "a student owns a cat"

In this exercice we have to assume that the events D and C are independent which means that none of them influence the occurence of the other. Because if they are not independent there really is noway to deduce q here.

In reality those events would probably not be independent since if I had a dog, I would really think twice before buying a cat; )

Well if they are independent then you know that The Probability of occurence of D and C at the same time equals P (D) * P (C) = p*q

So we can deduce that 2/15=1/3*q

q=3*2/15

q=6/15

q=2/5

Once again this is theoritical