The table given below shows the months of birth of 40 students of a class in a school .

If one student is chosen at random , what is the probability that the student is born
(i) in the latter half of the year ?
(ii) in a month having 31 days ?
(iii) in a month having 30 days ?

Explanation

Total number of students in the class = 40.
(i) Let `E_(1)` be the event that the chosen student is born in the latter half of the year . Then ,
`P(E_(1)) = ("no., of students born in latter half of the year ")/(" total number of students ")`
`= (2 + 6 + 3 + 4 + 4 + 4)/(40) = (23)/(40) = 0.575`
(ii) Let `E_(2)` be the event that the chosen student is born in a month having 31 days . then ,
`P(E_(2)) = ("number of students born in a month having 31 days")/("total number of students")`
`= (3 + 2 + 5 + 2 + 6 + 4 + 4 )/(40) = (26)/(40) = (13)/(20) = 0.65`
(iii) Let `E_(3)` be the event that the chosen student is born in a month having 30 days . then ,
`P(E_(2)) = ("number of students born in a month having 30 days")/("total number of students ")`
= `(2 + 1 + 3 + 4)/(40) = (10)/(40) = (1)/(4) = 0.25`.