1. Shopper Trak is a hidden electric eye designed to count the number of shoppers entering a store. When two shoppers enter the store together one walking in front of the other, the following possibilities apply. There is a 0.98 probability that the first shopper will be detected and a 0.94 probability that the second shopper will be detected and a 0.93 probability that both of them will be detected by the device. What is the probability that the device will detect at least one of the two shoppers entering together?
2. A statistics professor has found that the probability is 0.74 that a student gets a B- or above for the final examination. He also found that the probability of 0.67 that a student gets a B- or above for both the final exam and the course. If a randomly selected student has already gotten a B- or above for the final exam taken yesterday what is the probability he will get a B- or above for the course when the grade report arrives next week?