TomJerry
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Question:
Five persons in a group of 20 are grauduate. If 3 are picked out of 20 at random,
i) compute the probability that all are graduate
ii) find atleast one being graduate.
Solution:
i) P(all grauduate being selected) = 5C3 / 20C3 [Is this correct]
ii) P(atleast 1 being graduate) = (5C1 . 15C2 / 20C3) + (5C2 . 15C1 / 20C3) + (5C3 . 15C0 / 20C3) [Is this correct]
Five persons in a group of 20 are grauduate. If 3 are picked out of 20 at random,
i) compute the probability that all are graduate
ii) find atleast one being graduate.
Solution:
i) P(all grauduate being selected) = 5C3 / 20C3 [Is this correct]
ii) P(atleast 1 being graduate) = (5C1 . 15C2 / 20C3) + (5C2 . 15C1 / 20C3) + (5C3 . 15C0 / 20C3) [Is this correct]