InterviewSolution
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InterviewSolution
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A telephone number has seven digits, no number starts with 0. In a city, how many different telephone numbers the formed using the digits 0 to 6? (Each digit can occur only once)A. 6!B. 6.6!C. 7!D. 2.7! |
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Answer» (i) The first digit of the number cannot be zero, so it can filled in 6 ways. (ii) Now the second digit can be any of the 6 digits, i.e., it can be filled in 6 ways. (iii) As the digits cannot be repeated, the number of ways the third digit can be filled is 5 ways and so on. (iv) Now apply the fundamental theoram. |
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