A box contains 2 red, 4 white, and 3 black pens. Two pens are drawn at random. What is the probability that they are of different colours? 

A terrorist is running on the road and three snipers of the army are taking a shot at it simultaneously. The probability of three snipers hitting the target are$\frac{1}{15},\frac{1}{16}and\frac{1}{5}$. Find the probability that exactly one of them shoots the terrorist.

A coin is tossed four times. Find the probability that there is at least one head.

Two cards are drawn simultaneously from a well shuffled pack of cards. Find the probability of both being black honours.

There are 7 people sitting around a circular table. Find the number of ways they can be seated?

A number (N) is chosen from (A) where A is set comprising of [–4, –3, 2, –9, 10, 12, 13]. What is probability that |N| < 10. 

Calculate the number of diagonals that can be drawn by joining the vertices of a decagon?

If there are ten letters and ten envelopes, I have placed the nine letters in right envelopes, in how many can I put the last one letter in wrong envelope?

In how many ways a committee consisting of 5 men and 6 women can be formed from 8 men and 10 women?

Reboot Pvt Ltd. manufactures RAM for several computer manufacturers. They have a testing process before the product is sent to the client. The probability that RAM will be defective is $\frac{1}{20}$, and the testing will give the correct result is $\frac{4}{5}$. Find the probability that if we pick up a RAM randomly, it is found to be defective.

In a party, each person shook hands with every other person present. The total number of handshakes was 28. Find the number of people present in the party.

The probability of occurrence of two events A and B is $\frac{1}{4}$ and $\frac{1}{8}$ respectively. If the probability of both A and B happen simultaneously is$\frac{4}{25}$. What is the probability of occurrence of either A or B?

A box contains 4 red pens, 5 blue pens, and 6 black pens. If one pen is drawn at random. Find the probability that it is a black pen.

How many three letter words can be formed using the letters of the word “PRACTICES”?

Two dice are rolled simultaneously. Find the probability that the sum of the numbers on them is not 8.