The probability of an event X is 2/3 and that of another event Y is 1/4. If the probability of either X or Y is

A university undergraduate has to take 5 courses from a pool of 4 Mathematics and 3 Physics courses.
In how many ways can she select her courses so that she takes exactly two courses in Physics?

The data below shows the distribution of workers in a certain secondary school. 

Teacher  30                                  Gardeners      15
Typists   9                                     Cleaners          6
Clerks   12                                     Messengers     3

If one of the workers is absent from work on one particular day, the probability that he is a clerk is

A bag contains 6 red balls, 12 white balls and 9 green balls.
A ball is selected at random.
What is the probability that it is a green ball?

A group of 40 adults read either newspapers or magazines.
If 20 read newspapers and 35 read magazines,
the probability that one of them reads both newspapers and magazines is

A bag contains 6 red balls, 9 blue balls and 5 green balls.
Two balls are chosen one after the other with replacement.
What is the probability that one is blue, the other is green?

Two dice, one red and the other blue are rolled together.
How many possible outcomes altogether

A university undergraduate has to take 5 courses from a pool of 4 Mathematics and 3 Physics courses.
In how many ways can she select her courses so that she takes at least two courses in Physics?

A bag contains only gala and royal apples.
The probability of picking a gala at random is 0.3.
Find the probability of picking a royal apple

P is a probability function of an exhaustive set S = {w, x, y, z}.
If P(x) = 1/4, P(y) = 1/3, P(z) = 1/6,
then P(w) is

A coin is tossed 3 times.
What is the probability of getting 2 heads and a tail in any order?

Three guests X, Y and Z arrive in that order for a dinner party.
If guests are served randomly, the probability that the three guests will be served in the sequence of their arrival is

A letter is chosen at random from the alphabet.
Find the probability that it is not one of the letters of the word DIAMOND

A container has 32 blue pens, 28 black pens and 20 red pens.
If a pen is selected at random,
what is the probability that it is not a red pen?

Three balls are drawn one after the other, without replacement from a bag containing 4 blue, 6 white and 5 red identical balls.
The probability that the three balls are:
one blue, one white and one red is

A bag contains 6 red balls, 12 white balls and 9 green balls.
A ball is selected at random.
What is the probability that it is not a green ball?

A bag contains 6 red balls, 9 blue balls and 5 green balls.
Two balls are chosen one after the other with replacement.
What is the probability that both are red?

A university undergraduate has to take 5 courses from a pool of 4 Mathematics and 3 Physics courses.
In how many ways can she select her courses if she insists on taking all four Mathematics courses?

A bag containing 5 red balls and 3 green balls.
Two balls are picked, one after the other, with replacement.
The probability that both are the same colour is

Two events M and N are mutually exclusive and P(M) = ¼ and P(N) = 2/3.
P(M∪N) is

A coin is tossed 3 times.
What is the probability of getting three tails?

What is the probability of throwing a number greater than 2 with a single in a fair die

A die is rolled 100 times with the following outcomes:

Number        1       2        3        4        5         6
Frequency   15     20      18      14      17       16

The experimental probability of obtaining a 2 is

The letters of the word MISSISSIPPI are cut and placed in a bag.
If one letter is drawn randomly from the bag,
the probability that it is neither an I nor a S is

Three balls are drawn one after the other, without replacement from a bag containing 4 blue, 6 white and 5 red identical balls.
The probability that all three balls are the same colour is