question 25 Math need help please

Question

in a class of 50 students, 34 are democrats, 6 are business majors, and 4 of the business majors are democrats if one student is randomly selected from the class find the probability of choosing a Democrat or a business major.

Answer 1

Let A be the event: Student is a democrat Then Pr ( A ) = 34 / 50

Let B be the event: Student is a business major. Then Pr ( B ) = 6 / 50

Also we know that Pr ( A and B ) = 4/40

Then using the formula for the union of two events, we have:

Pr ( A or B ) = Pr ( A ) + Pr ( B ) - Pr ( A and B )

34 / 50 + 6 / 50 - 4 / 50 = 36 / 50 = 18 / 25