The number of digits in a mobile phone number decide the maximum mobile phones we can have without dialing the country code, ie. 91 (for India). To understand this we need to go back to school.Remember permutations & combinations.
Suppose I had a pair of jeans (J1-2) and four tee-shirts (T1-4). The possible combinations are J1T1, J1T2, J1T3, J1T4, J2T1, J2T2, J2T3, and J2T4, ie. 8 combinations {2 (no. of jeans) X 4 (no. of tee-shirts)}.
The same logic is used when computing the digits in a mobile phone number. Now suppose if we had a 6-digit cell number, the maximum number of unique cell numbers possible would have been (10 x 10 x 10 x 10 x 10 x 10), ie, a maximum of 1,000,000 subscribers. We have already crossed the 100-million mark in India. So obviously we could not have had a 6-digit cell phone number. Not even a 7-digit because that would've resulted in a capacity of 10 million, not even 8-digit (100 million subscribers), and not even a 9-digit (ie. 1000 million or 100 crores, since our population is close to 125 crores and growing).
A 10-digit cell number offers us a capacity to have 10 million (1000 crore) subscribers, which is far more than what our country can even achieve. We are v.v.v.unlikely to have a population or a subscriber base of 1000 crore but there is a remote likelihood of us having 100 crore subscribers. Hence, a 10-digit mobile number.
There are 9 digits that can be the first digit (1-9); for each of these there is 1 digit that can be the second digit (6); for each of these there are 10 digits that can be the third digit (0-9); for each of these there are 10 digits that can be the fourth digit (0-9). → number of numbers is 9 × 1 × 10 × 10 = 900 such numbers.
5 digit telephone numbers having at least one of their digits repeated is = total possible 5 digit telephone numbers - 5 digit telephone numbers without any digit being repeated. =(10*10*10*10*10)-(10*9*8*7*6) =100000-30240 =69760
99. But only if you consider the first nine as 01, 02, 03 etc. If not, there are 90 2-digit numbers, starting with 10 and ending with 99.
There are 900 natural numbers made up of only three digits. This is because there are 9 options for the first digit (1-9), 10 options for the second digit (0-9), and 10 options for the third digit (0-9). Multiplying these options together gives us 9 x 10 x 10 = 900 possible three-digit natural numbers.
There are 90 two-digit numbers... starting with 10 and ending with 99.
Yes, mobile phones in Ireland do have 10 digit numbers.
There are no reliable statistics on the total number of telephone numbers.
There are 9 digits that can be the first digit (1-9); for each of these there is 1 digit that can be the second digit (6); for each of these there are 10 digits that can be the third digit (0-9); for each of these there are 10 digits that can be the fourth digit (0-9). → number of numbers is 9 × 1 × 10 × 10 = 900 such numbers.
Without restrictions, it was would numbers 000-000-0000 through 999-999-9999. So that would be 9,999,999,999 + 1 = 10 billion different 10-digit phone numbers. Ex: If there existed single digit phone numbers, there would be 10, because the digits are 0 through 9. If there existed only double digit phone numbers, then it would be 00 through 99 which would be 100 total two-digit numbers. Therefore the total possible combinations for an X digit phone number would be: 10^X
5 digit telephone numbers having at least one of their digits repeated is = total possible 5 digit telephone numbers - 5 digit telephone numbers without any digit being repeated. =(10*10*10*10*10)-(10*9*8*7*6) =100000-30240 =69760
No one-digit numbers are divisible by 10. 10 is divisible by 1, 2 and 5.
99. But only if you consider the first nine as 01, 02, 03 etc. If not, there are 90 2-digit numbers, starting with 10 and ending with 99.
There are 900 natural numbers made up of only three digits. This is because there are 9 options for the first digit (1-9), 10 options for the second digit (0-9), and 10 options for the third digit (0-9). Multiplying these options together gives us 9 x 10 x 10 = 900 possible three-digit natural numbers.
10 digit numbers
the right answer is 10 cause there is o,1,2,3,4,5,6,7,8,9 so there 10 numbers in total which have 1 digit
There are 90 two-digit numbers... starting with 10 and ending with 99.
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