Two unbiased dice are thrown once. Write all the possible outcomes of this experiment. What is the probability that the sum of numbers on two dice is a factor of $18$?

Box $A$ contains $25$ slips of which $19$ are marked $Rs. 1$ and others are marked $Rs. 5$ each. Box $B$ contains $50$ slips of which $45$ are marked $Rs. 1$ each and others are marked $Rs. 13$ each. Slips of both boxes are poured into a third box and reshuffled. $A$ slip is drawn at random. What is the probability that it is marked other than $Rs. 1$?

In a packet of $500$ screws,$80$ screws are defective. Find the probability that a screw selected at random from the packet is non-defective. (in $/25$)

There are $5$ white,$7$ red,$4$ black,and $2$ blue identical balls in a box. One ball is selected at random from the box. Find the probability that the selected ball is not white.

An unbiased coin is tossed thrice. Find the probability of the following event:
$B:$ at least $2$ heads are received.

Two balanced dice are rolled simultaneously. Then,the probability that the sum of numbers on the dice is $7$ is ............