Answer: 90,000
Explanation:
A Company has to provide 5-digit numbers(The first digit≠0)
This question can be solved with Permutations and Combinations
Assume there are 5 blank spaces representing any phone number
The first digit can be filled in 9 ways(excluding 0 ={1,2,3,4,5,6,7,8,9})
The second digit can be filled in 10 ways(no exemptions={0,1,2,3,4,5,6,7,8,9})
The third digit can be filled in 10 ways(no exemptions={0,1,2,3,4,5,6,7,8,9})
The fourth digit can be filled in 10 ways(no exemptions={0,1,2,3,4,5,6,7,8,9})
The fifth digit can be filled in 10 ways(no exemptions={0,1,2,3,4,5,6,7,8,9})
So total number of ways to fill the 5 blanks
⇒Total number of 5-digit phone numbers= 90000
Hope this helps, Have a good day :))))