CampusFest is a student festival where local businesses come on campus to sell their goods to students atvastly reduced prices. As part of a give-away promotion, a local cellular phone company gave away 300cellular phones to students who signed up for their calling service. Unbeknownst to the company is that 20 ofthese cellular phones were faulty and will cause a small explosion when dialed outside the local calling area.Suppose you and your roommate each received one of the giveaway phones. Find the probability that both ofyou received faulty phones. Round to five decimal places when necessary.
A) 0.00424
B) 0.00444
C) 0.13333
D) 0.06243

Question

Quizplus · Accepted Answer

The probability that one phone is faulty is 20/300. The probability that the second phone is also faulty, given the first one is faulty, is 19/299. Multiplying these probabilities gives (20/300) * (19/299) = 0.00424.

CampusFest Is a Student Festival Where Local Businesses Come on Campus