Students need a 4-character password to log onto school computers. The first two characters are letters of the alphabet and may not be repeated. The last 2 are digits from 1 through 9 and can be repeated. How many different passwords are possible? Please show me the steps.

Question

Students need a 4-character password to log onto school computers.  The first two characters are letters of   the alphabet and may not be repeated.  The last 2 are digits from 1 through 9 and can be repeated.  How many different passwords are possible? Please show me the steps.

anonymous · Answer

permutation problem. i hope i can answer this, lol

for the first 2 characters of the password which is given to be fix, therefor there are no other way to replace them.  the problem here is the last two chracters whose option is 1-9 and can be repeated. .

anonymous · Answer

The short answer is there are 52650 possible combinations. For the explanation: There are 26 possible options at the first character, but when you picked 1 out of the 26 letters you only have 25 possible options for the 2nd character. That because 1st and 2nd can't be the same. There are also 9 possible numbers for 3rd character and 9 for the 4th character. So all in all: 26 * 25 * 9 * 9 =52650

anonymous · Answer

aah, yeah. .  sorry i fail to read the given for the first 2 characters. lol

anonymous · Answer

Thanks to both of you !