What is the probability that a number selected at random from the number 1, 2, 2, 3, 3, 3, 4, 4, 4, 4 will be their average?

In a class, there are 18 girls and 16 boys. The class teacher wants to choose one pupil for class monitor. What she does, she writes the name of each pupil on a card and puts then into a basket and mixes thoroughly. A child is asked to pick one card from the basket. What is the probability that the name written on the card is:

(i) the name of a girl

(ii) the name of a boy

Why is tossing a coin considered to be a fair way of deciding which team should choose ends in a game of cricket?

The faces of a red cube and a yellow cube are numbered from 1 to 6. Both cubes are rolled. What is the probability that the top face of each cube will have the same number?

The probability of selecting a green marble at random form a jar that contains only green, white and yellow marbles is 1/4. The probability of selecting a white marble at random form the same jar is 1/3. If this jar contains 10 yellow marbles. What is the total number of marbles in the jar?