How many ways can 7 digit numbers can be formed if repetition is not allowed?

For the third place we have 8 options to choose from 0 to 9 excluding the digits we already placed on first and second positions. Hence the answer appears. Also there will be 6∗6∗5∗4∗3∗2∗1=4320 seven digit numbers having the digits 0,1,2,3,4,5,6 giving minimum sum as 21.

How many 7 digit numbers can be formed using 0 9?

Assuming repetition is allowed, you can have 7-digit numbers from 1,000,000 to 9,999,999 which is a total of 9,000,000 7-digit numbers. These are all the possible 7-digit numbers. In general, there are 9 × 10^(n-1) possible n-digit numbers.

How many 7 digit numbers can be formed using the digits from 2 to 9 if repetition of digits is not allowed?

There are 9 digits you can have for the first digit (can’t have 0). There are then 9 more for the second (all except the first one). Similarly there are 8 for the third, 7 for the 4th, etc… So the total would be 9*9*8*7*6*5*4 = 544,320 7 digit numbers without repeated digits.

How many 7 digit numbers can be formed numbers can be repeated but the first number Cannot be 0?

So the total number of ways in which 7-digit phone numbers are possible assuming that the first digit can’t be a 0 or a 1 are 8 * 10^6 = 8000000 including repetition.

How many 7 digit numbers can be formed by using the numbers 1 2 and/or 3?

We know that the factorial can be written by the formula n! =n×(n−1)! Therefore, the number of different seven-digit numbers that can be written using only three digits 1,2 and 3 is 672. Thus, option (A) is the correct answer.

Can a 7 digit phone number start with 0?

Several cities were upgraded in this period to seven-digit (two-letter-five-number) phone numbers. As there are no letters on the 0 or 1 position, it fit with the assumption that no central office code would have a zero or one as the middle digit.

How many 7 digit numbers are there having the digit 3 three times and the digit 0 four times )?

Latest Book Aptitude Question SOLUTION: How many 7 digit numbers are there having the digit 3 three times and the digit 0 four times. Ans :15.

How many seven digit numbers can be formed if the first digit Cannot be zero and the last digit Cannot be 1?

Therefore, we have 544320 ways of seven-digit phone numbers can be formed if the first digit cannot be 0 and repetition of digits is not permitted.