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1. b)Week spots occur at random in the manufacture of certain cable at an average rate of 1 per 100 meters. If X represents the number of weak spots in 100 meters of cable, write down the distributions of X. Lengths of this cable are wound onto drums.(1) Each drum carries 50 meters of cable. Find the probability that a drum will have 3 or more weak spots.(2)A contractor buys five such drums. Find the probability that two have just one weak spot and the other three have none.
2. (Original post by Bookwormprincess)
b)Week spots occur at random in the manufacture of certain cable at an average rate of 1 per 100 meters. If X represents the number of weak spots in 100 meters of cable, write down the distributions of X. Lengths of this cable are wound onto drums.(1) Each drum carries 50 meters of cable. Find the probability that a drum will have 3 or more weak spots.(2)A contractor buys five such drums. Find the probability that two have just one weak spot and the other three have none.
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