In a certain town,$40\%$ of the people have brown hair,$25\%$ have brown eyes,and $15\%$ have both brown hair and brown eyes. If a person selected at random from the town has brown hair,what is the probability that they also have brown eyes?

$A$ bag contains $3$ red and $7$ black balls. Two balls are taken out at random,without replacement. If the first ball is red,what is the probability that the second ball is also red?

If $A$ and $B$ are two events such that $P(A) = \frac{3}{8}$,$P(B) = \frac{5}{8}$ and $P(A \cup B) = \frac{3}{4}$,then $P(A|B) = $

$A$ bag contains $3$ white and $7$ red balls. If a ball is drawn at random,what is the probability that the drawn ball is either white or red?

In an entrance test,there are multiple-choice questions. There are four possible answers to each question,of which one is correct. The probability that a student knows the answer to a question is $90\%$. If he gets the correct answer to a question,then the probability that he was guessing is:

When two dice are rolled,what is the probability that the sum of the numbers appearing is a multiple of $3$?