There are 35 students in a class of whom 20 are boys and 15 are girls. From these students one is chosen at random. What is the probability that the chosen student is a (i) boy, (ii) girl?
Total numbers of students are: 35
(i) Let E be the event of choosing a boy at random
Then, the numbers of favourable outcome are: 20
∴ P (choosing a boy) = P (E) = 20/35 = 4/7 or 57%
(ii) Let E be the event of choosing a girl at random
Then, the numbers of favourable outcome are= 15
∴ P (choosing a girl) = P (E) = 15/35 =3/7 or 43%