Question

To use an automated teller machine at a certain​ bank, you must enter a 3​-digit ​code, using the digits 1 dash 9. How many 3​-digit codes are possible if repetition of digits is​ permitted?

Answer 1

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