Question 1136995
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A factory has seven machines- four of model A and three of model B. At any given moment, there is an 80% chance that a model A machine 
will be in use. Similarly, model B is used 60 % of the time. If the supervisor walks into the factory at a randomly selected time, 
what is the probability that {{{highlight(exactly)}}} two machines of model A and {{{highlight(exactly)}}} one of model B will be in use? 
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P = {{{C[4]^2*0.8^2*(1-0.8)^2}}} + {{{C[3]^2*0.6*(1-0.6)^2}}} = {{{6*0.8^2*0.2^2 + 3*0.6*0.4^2}}} = 0.4416 = 44.16%.
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