A box contains $6$ red, $5$ blue and $4$ white marbles. Four marbles are chosen at random without replacement. The probability that there is atleast one marble of each colour among the four chosen, is?

Q. A jar of marbles contains $4$ blue, $5$ red, $1$ green and $2$ black marbles. A marble is chosen at random from the jar. After replacing it, a second marble is chosen. Find the probability of choosing a green and then a red marble.

Q. An urn contains marbles of four colours : red, white, blue and green. When four marbles are drawn without
replacement, the following events are equally likely :
(1) the selection of four red marbles;
(2) the selection of one white and three red marbles;
(3) the selection of one white, one blue and two red marbles;
(4) the selection of one marble of each colour.
The smallest total number of marbles satisfying the given condition is

Q. A jar contains 2 green marbles, 4 blue marbles, 3 yellow marbles and 2 black marbles. A marble is chosen at random from the jar and replaced. Then a second marble is chosen at random. What is the probability of the first marble being green and the second marble being yellow?

Q. An urn contains marbles of four colours: red, white, blue and green. When four marbles are drawn without replacement, the following events are equally likely:
$\left(1\right)$ the selection of four red marbles;
$\left(2\right)$ the selection of one white and three red marbles;
$\left(3\right)$ the selection of one white, one blue and two red marbles;
$\left(4\right)$ the selection of one marble of each colour.
The smallest total number of marbles satisfying the given condition is.

Q. A bag contains $7$ blue marbles, three red marbles, and two white marbles. If one marble is chosen at random from the bag, what is the probability that it will not be blue?