Here's the question you clicked on:
smicatrotto
The mathematics department of a college has 12 male professors, 10 female professors, 11 male teaching assistants, and 6 female teaching assistants. If a person is selected at random from the group, find the probability that the selected person is a teaching assistant or a female. I got 9/13... but for some reason I think that's wrong. Just want to make sure before I submit.
(10 + 11 + 6)/(10 + 11 + 6 + 12) = 9/13
As a general rule for probabilty, add up the possible outcomes and divide that by the total outcomes, as slaaibak did above.