Question

how many possibilities of numbers are there (10 digit numbers) the telephone numbers

Answer 1

Using permutations , I am telling you the answer,

We have 10 Single digit numbers, That are,

0,1,2,3,4,5,6,7,8,9 ,

We know that 0 can't come in the first 10 digit telephone number, because if it comes, Then the number will be 9 digit number,

Also we can repeat numbers in the 10 digits,

Possible values for 1st place = 9,
Possible values for every other place = 10,

Now applying permutations, The total no. of 10 digit telephone numbers that are possible are,

9*10*10*10*10*10*10*10*10*10

= 9000000000,

These number of Telephone numbers can be formed,

Hope you understand, Have a great day !

Answer 2

Answer:

refers to the attachment