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mimetex cgi p+=+0 4+ cdot + left frac 1 2 right +++0 1+ cdot + left frac 1 2 right +=+0 25

mimetex cgi p+=+0 4+   cdot  + left  frac 1  2  right +++0 1+   cdot  + left   frac 1  2  right +=+0 25

Summary: Your method 2 would first find that the probability of a randomly selected modem from the whole population being defective is and then conclude that the probability of exact one defect in a two element sample from the population is

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