Question
Question: The number of five digit telephone number having at least one of their digits repeated is –...
The number of five digit telephone number having at least one of their digits repeated is –
A
90000
B
100000
C
30240
D
69760
Answer
69760
Explanation
Solution
Total telephone Nos. can be formed = 105
Nos. in which no repetition = 10P5 = 30240
So in which repetition are there =105 – 30240 = 69760