How many four-digit numbers can be formed using the digits 0,1,2,3, 4,5 without repetition?
How many four-digit numbers can be formed using the digits without repetition?
A
B
C
D
Solution:
For a four-digit number, we have to fill four places and
cannot appear in the first place (thousand's place).
For the first place, there are five choices (
); Second place can then be filled in five ways (
and remaining four-digits); Third place can be filled in four ways (remaining four-digits); Fourth place can be filled in three ways (remaining three-digits).
Total number of ways =
four-digits numbers can be formed.
