The phone company requires callers to dial 10 digits instead of 7 because it was running out of phone numbers. The number of possible 10-digit phone numbers is 100 times larger than the number of possible 7-digit phone numbers. Does this make sense? Explain
Please help because I'm very stuck!
2006-11-01 15:47:05 · 6 answers · asked by Cheza 2 in Science & Mathematics ➔ Mathematics
I liked both iggry's and topher8128's answer but iggry's was the first one I understood and topher8128 gave more details, thanks to both answers
2006-11-04 06:32:49 · update #1
A 7 digit phone number is 100-0000, or 1,000,000 (each number has 7 digits just written a different way).
Similarly, a 10 digit phone number is 100-000-0000 or 1,000,000,000.
So rephrasing the question, is 1 billion 100 times larger than 1 million...
This question is easier, which is always nice :)
No... 1,000,000 is a thousand times larger than 1,000,000,000. Therefore there are 1000 times more 10 digit phone numbers than 7 digit phone numbers.
2006-11-01 15:56:30 · answer #1 · answered by iggry 2 · 0⤊ 1⤋
No. The new number of possible phone numbers is 1000. Calculated by 10 x 10 x 10, where each 10 represents the number of new digits being 3.
Think about it. By adding 1 extra digit, you can have all the previous combinations with 0 to 9 placed in from, representing 10 times more numbers. Add another digit and you get a multiple of another 10 numbers and so on.
2006-11-01 15:50:53 · answer #2 · answered by Anonymous · 0⤊ 1⤋
For any spot in the phone number, you can insert any digit (10 possibilities).
If phone numbers are one digit, you can have 10 numbers.
If phone numbers are two digits, you can have 100 numbers.
For any number of digits, the number of combinations is 10^n, where n is the number of digits in the phone number.
If you are familiar with exponents, you will see that:
10^10 / 10^7 = 10^3 = 1000.
There are 1000 times as many 10-digit telephone numbers.
2006-11-01 15:56:55 · answer #3 · answered by topher8128 2 · 1⤊ 0⤋
No...It's more...
The first digit can't be a one or a zero...So there are eight hundred(8*10*10 2-9, 0-9, 0-9) times more phone numbers...But you have to take out 800, 888, 877, 866 and 900 so there are 795 times more phone numbers with 10 digit numbers than with 7 digit numbers
2006-11-01 15:52:47 · answer #4 · answered by feanor 7 · 0⤊ 0⤋
A 7 digit number has a possible total numbers of 9999999. Add three more digits and you have total numbers of 9999999999
About 100 times larger.
2006-11-01 15:52:15 · answer #5 · answered by kellenraid 6 · 0⤊ 1⤋
yes because you have 3 more numbers which makes more possiblities.
2006-11-01 15:54:23 · answer #6 · answered by Anonymous · 0⤊ 0⤋