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Question 18 Keep using the following info for this question and the next 2 questions: Three machines are available to cut concrete blocks. Each machine needs to be brought down from time to time for maintenance. At any given moment, the probability that a machine is down is 0.1, and the probability that it is functioning is 0.9. Assume the machines function independently. Let x be the number of machines that are functioning Find the probability mass function of x = 1, i.e. p(x = 1). [answer should be in decimal form, rounded to 3 decimal places]