Answer:
729 , 3- digit codes are possible
Step-by-step explanation:
To use an automated teller machine at a certain bank, you must enter a 3-digit code, using the digits 1 dash 9.
We need a 3 digit code using digits 1 to 9
so total of 9 digits are used
also repetition of digits are permitted
In a 3 digit code, first digit can be any number from 0 to 9
so 9 possible numbers for first digit.
since repetition is allowed so second and third digit also have any number between 0 to 9
3 digit code
------ , ------- , --------
9 possibilities for each place
---9--- , ----9--- , ----9----
9 *9 *9 = 729
so 729 , 3- digit codes are possible
