Find the number of possible events, if

(i) n coins are tossed together

(ii) n dice are thrown together

The blood groups of 30 students of class IX are recorded as follows :

A, B, O, O, AB, O, A, O, B, A, O, B, A, O, O

A, AB, O, A, A, O, O, AB, B, A, O, B, A , B, O

A student is selected at random from the class from blood donation. Find the probability that the blood group of the student chosen is :

(i) A

(ii) B

(iii) AB

(iv) O

The record of a weather station shows that out of the past 250 consecutive days, its weather forecast was correct 175 times. What is the probability that on a given day

(i) Was it correct?

(ii) Was it incorrect?

In a bag, there are red, white, blue and black balls. If the probability of drawing a red ball is x/2, the probability of drawing a white ball is x/3, the probability of drawing a blue ball is 1/2. Find the probability of drawing a black ball.

In a football match, Ronaldo makes 4 goals from 10 penalty kicks. Find the probability of converting a penalty kick into a goal by Ronaldo.