SOLUTION: A campus telephone extension has four digits. If the first digit cannot be 0, how many different extensions exist?
Algebra.Com
Question 1001359: A campus telephone extension has four digits. If the first digit cannot be 0, how many different extensions exist?
Answer by ikleyn(52800) (Show Source): You can put this solution on YOUR website!
.
There are 9 options for the first digit (1, 2, 3, 4, 5, 6, 7, 8, 9);
10 options for the second digit;
10 for the third, and
10 for the fourth digit.
In total, there are 9*10*10*10 = 9000 options for 4-digit extension.
RELATED QUESTIONS
the telephone extensions at a company use 4 digits
a. how many extensions are possible... (answered by stanbon)
the telephone extensions at a company use 4 digits
a. how many extensions are... (answered by stanbon,checkley77)
How many six-digit telephone numbers are possible if the first digit cannot be a... (answered by sudhanshu_kmr)
How many seven-digit telephone number can be formed if the first three digits cannot be... (answered by stanbon)
How many different four-digit numbers can be formed from the digits 0 through 9 if the... (answered by solver91311)
How many different four digit numbers can be formed from the digits 0 through 9 if the... (answered by josmiceli)
How many different four-digit numbers can be formed from the digits 0 through 9 if the... (answered by stanbon)
How many different four-digit numbers can be formed from the digits 0 through 9 if the... (answered by stanbon)
How many different four-digit numbers can be formed from the digits 0 through 9 if the... (answered by stanbon)