a) A husband and wife appear in an interview for two vacancies in the same post. The probability of husband's selection is 1/7 and that of wife's selection is 1/5.
What is the probability that
i) Both of them will be selected
ii) Only one of them will be selected
ii) None of them will be selected
b) In a factory, Machine A produces 30% of the output. Machine B 25% and Machine C produces the remaining 45%. 1% of the output of Machine A is defective, 1.2% of B's and 2% of C's. In a day's run the three machines produces 10,000 items. An item is drawn at random from a day's output and is defective.
What is the probability that it was produced by
i) Machine A
ii) Machine B
iii) Machine C