Six boys and six girls sit in a row. What is the probability that the boys and girls sit alternatively?

Study the given information carefully to answer the question that follows. An urn contains $4$ green,$5$ blue,$2$ red,and $3$ yellow marbles. If $2$ marbles are drawn at random,what is the probability that both are red or at least $1$ is red?

$A$ box contains $6$ nails and $10$ nuts. Half of the nails and half of the nuts are rusted. If one item is chosen at random,what is the probability that it is rusted or is a nail?

$A$ basket contains $4$ red,$5$ blue,and $3$ green marbles. If three marbles are picked at random,what is the probability that at least one is blue?

$A$ group of $4$ students is to be formed from among $4$ girls and $6$ boys. What is the probability that the group has less number of boys than the number of girls?

$A$ bag contains $3$ white and $2$ black balls and another bag contains $2$ white and $4$ black balls. $A$ ball is picked up randomly. The probability of its being black is