Question
A telephone number has seven digits, no number starts with $0 .$ In a city, how many different telephone numbers be formed using the digits 0 to $6 ?$ (each digit can occur only once)(1) $6 !$(2) $6.6 !$(3) $7 !$(4) $2 \cdot 7 !$
Step 1
Therefore, for the first digit, we have six possible options (1, 2, 3, 4, 5, 6). Show more…
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how many 7-digit phone numbers can be formed if the first digit cannot be 0 or 1, and any digit can be repeated
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