A troubled stats student decided there was only a 30 probabi

A troubled stats student decided there was only a 30% probability that he was going to pass the class but that there was a 60% chance that he was going to get a date with the girl sitting beside him. He decided the probability of both occurring was too depressing to consider so he decided to calculate the probability of either one or the other occurring. Can you help him out? What is the probability of either passing or getting the date?

A. 18% B. 45% C. 72% D. 82%

Solution

P( either one of occuring) = 1 - P( none will occur) = 1 - (1-0.30) ( 1-0.60) = 0.72 = 72%