digits should be 9-2-9
2006-08-07 02:13:40 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
same as the others ...
929 ****
_ _ _ _
the underlines represent the numbers to be placed...
since in a telephone number we can repeat numbers... all we have to do is
10 10 10 10
10*10*10*10 = 10000
there would be 10000 7-digit telephone numbers
10 because the numbers are from 0~9
2006-08-07 02:27:25 · answer #1 · answered by Hi-kun 2 · 0⤊ 0⤋
If the first three digits are fixed, then the question really becomes how many 4-digit numbers are there?
The answer, of course, is 10,000 (0000 thru 9999)
Doug
2006-08-07 02:19:36 · answer #2 · answered by doug_donaghue 7 · 1⤊ 0⤋
For any given three digit prefix with a total of seven digits in the phone number, it is possible to have 10,000 different phone numbers.
2006-08-07 02:23:06 · answer #3 · answered by Anonymous · 0⤊ 0⤋
10 * 10 *10 *10 = 10000
is the answer if repitation of number is allowed
2006-08-07 02:28:48 · answer #4 · answered by Jatta 2 · 0⤊ 0⤋
10000
2006-08-10 19:24:59 · answer #5 · answered by epchacon 2 · 0⤊ 0⤋
9-2-9-x-x-x-x
possibilities of x is 10
10*10*10*10=10,000 possible combinations
2006-08-07 03:27:43 · answer #6 · answered by Croasis 3 · 0⤊ 0⤋
only the last 4 digits are variable?
then 10,000
0000 through 9999
I think.
2006-08-07 02:19:11 · answer #7 · answered by notsureifimshy 3 · 0⤊ 0⤋
that would be 10*10*10*10 = 10,000
2006-08-07 02:46:46 · answer #8 · answered by sk_yahoo 2 · 0⤊ 0⤋