A Book contains 100 pages . a page is chosen at random. what is the chance that the sum of the digits on the page is equal to 9?
Answer :
We know Probability P ( E ) =
Here we have book contains 100 pages .
So,
Total number of events n ( S ) = 100
And
Pages that have sum of the digits on the page is equal to 9 = { 9 , 18 , 27 , 36 , 45 , 54 , 63 , 72 , 81 , 90 }
So,
Total number of desired events n ( E ) = 10
So,
Probability of getting sum of the digits on the page is equal to 9, P ( E ) =
We know Probability P ( E ) =
Here we have book contains 100 pages .
So,
Total number of events n ( S ) = 100
And
Pages that have sum of the digits on the page is equal to 9 = { 9 , 18 , 27 , 36 , 45 , 54 , 63 , 72 , 81 , 90 }
So,
Total number of desired events n ( E ) = 10
So,
Probability of getting sum of the digits on the page is equal to 9, P ( E ) =