ampusFest is a student festival where local businesses come on campus to sell their goods to students at vastly reduced prices. As part of a give-away promotion, a local cellular phone company gave away 400 cellular phones to students who signed up for their calling service. What the company doesn't know is that 30 of these 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 at least one of the two phones is faulty.

0.14455

Step-by-step explanation:

Since there are 30 faulty phones out of 400. It means that the Number of working phones are; 400 - 30 = 370

Probability that you will get a working phone = 370/400 = 37/40

Probability that your roommate will get a working phone after you have gotten = 369/399

Thus,probability that both of you will get a working phone = (37/40) × (369/399) = 0.85545

Finally, probability that at least one of the two phones is faulty = 1 - 0.85545 = 0.14455

typically if you want , you would actually put questions here for us to you. but hey, that's just me. maybe someone will magically answer the questions for you without knowing what they are.