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Three letters are randomly selected from the 26 capital letters of the English alphabet. What is the probability that letters A will not be included in the choice ?(a) \(\frac{1}{12}\)(b) \(\frac{23}{26}\)(c) \(\frac{12}{13}\)(d) \(\frac{25}{26}\) |
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Answer» (b) \(\frac{23}{26}\) Total number of ways in which 3 letters can be selected from 26 letters = 26C3. If A is not to be included in the choice, there are 25 letters left, so number of ways in which 3 letters can be selected without including A = 25C3. ∴ Required probability = \(\frac{^{25}C_3}{^{26}C_3}\) = \(\frac{25\times24\times23}{26\times25\times24}\) = \(\frac{23}{26}\). |
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