Question

A class contains 10 Management (M) majors and 20 World Climate (W) majors of which half the M and half the W majors have brown eyes (B). What is the correct expression to compute the probability that a person chosen at random is a management major or has brown eyes

Answer 1

5/6

Explanation:

Number of people in management majors = 10, number of people in world climate = 20.

Total number of people in class = Number of people in management majors + number of people in world climate = 10 + 20 = 30

Number of people with brown eyes = 10 / 2 + 20 / 2 = 5 + 10 = 15

Probability that a person chosen at random is a management major or has brown eyes = P(M or B)

P(M or B) = P(M) + P(B)

But probability of management major [P(m)] = Number of people in management majors / total number = 10 / 30 = 1/3

probability of brown eyes = Number of people with brown eyes / total number = 15 / 30 = 1/2

P(M or B) = P(M) + P(B) = 1/3 + 1/2 = 5/6