1. (3 marks! It is known that 20% of female students at certain school wear a ring, 30% of female students at this school wear a necklace, and 10% of female students wear both a ring and a necklace. a. The probability that a randomly selected female student at this school wears a ring or a necklace or both is b. The probability that a randomly selected female student at this school wears a ring given that this student wears a necklace is c. The probability that a randomly selected female student at this school wears a necklace given that this student wears a ring is 2. (3 marks! A re alarm system inside an ofce building has two types of activation devices, A and B, which operate independently. Probability that device A is turned on in the case of a re is 0.97. Probability that device B is turned on in the case of a re is 0.85. When there is a re, the re alarm system is turned on when at least one of two activation devices is turned on. a. Probability that both devices are turned on in the case of a re is b. Probability that the re alarm system is turned on in the case of a re is c. Probability that the re alarm system is not turned on in the case of a re is