Answer-The number of five–digit telephone numbers having at least one of their digits repeated is

Question

Answer-The number of five&ndash;digit telephone numbers having at least one of their digits repeated is

Accepted Answer

The number of fivendashdigit telephone numbers which can be formed using the digits of 0, 1, 2,...., 9 is 105. The number of five-digit telephone numbers which have none of their digits repeated is 10P5  10 times 9 times 8 times 7 times 6  30240 Hence the required number 105 - 30240  69760

The number of five–digit telephone numbers having

Solution

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The number of five&ndash;digit telephone numbers having

Solution

Relevant for Exams:

The number of five–digit telephone numbers having