Question

A physics class has 40 students. Of​ these, 18 students are physics majors and 17 students are female. Of the physics​ majors, seven are female. Find the probability that a randomly selected student is female or a physics major.

Answer 1

Probability (Physics Major or Female) = 28/40 = 0.7

Explanation:

The probability of being a female is 17/40

The probability of being a physics major is 18/40

The number of students counted twice is 7/40

Probability (Physics Major or Female) = 17/40 + 18/40 - 7/40

Probability (Physics Major or Female) = 28/40 = 0.7