Question

School band sold 30 raffle tickets each ticket is labeled with a number 1 to 31 winning ticket will be drawn what is the probability that the number of the winning ticket will be of four or the number 19 enter your answer as a fraction in the simplest form in the Box

Answer 1

0.27

Explanation:

To solve this problem, we will use Set Theory Approach to Probability.

Let U = the Sample Space which consists of all possible tests.

Of course U = {1,2,3 .... ,30}

So, no elements in that.

U = n = 30

Let Q = the event bearing a multiple of 4 No winning ticket, and,

R = the case that has the No. 19 winning ticket

∴

Q = { 4, 8, 12 , 16 , 20, 24 , 28} , and

R = {19} , so that

Q ∩ R = ϕ

P(Q ∩R ) = 0

As, n(Q) = 7 , n(R) = 1 , we have,

P (Q) =
`(n (A))/(n(U))` =
`(7)/(30)`, and P (R) =
`(1)/(30\\)`

P (Q∪R) = P(Q ) + P(R) − P(A∩B) =
`(7)/(30)` +
`(1)/(30\\)` − 0 =
`(8\\)/(30\\)`

≅ 0.27 .