following deetails show thebirth month of 40 students of class 9:

jan.-3, feb.-4,

march-2,april-2,

may-5,june-2,

july-2,aug.-5,

sep.-3,oct-4,

nov.-4,dec.-4..

find the probability that a student was born in august.

Actually the data is as follows

Jan-3, 

feb-4,

march-2,

april-2,

may-5,

june-1, ( not 2 )

july-2,

aug.-5,

sep.-3,

oct-4,

nov-4,

dec-4

Adding all the above we get = 39 

But total number of students born=40

40-39=1 student is born in any of the month

P( 1 student)= 1/40

5 students out of 40 are born in august

P ( students born in august)= (5/40) + (1/40)

 =6/40

 = 3/20