Question

To use an automated teller machine at a certain​ bank, you must enter a 4​-digit ​code, using the digits 0 dash 9. How many 4​-digit codes are possible if repetition of digits is​ permitted?

Answer 1

Answer:

100000 4-digit codes

Step-by-step explanation:

using the digits 0 dash 9, we want to pick 4 digits code.

The total number of digits available for us to pick from is 10(0 to 9 has 10 digits). We want to pick the 4 digits code and repetition is allowed. This is a case where we apply permutation with repetition. It is different when repetition is not allowed. It gives more possible outcomes than when repetition is not allowed. We will apply the formula, n^r

Where n is the total number of digits we want to choose from and it is equal to 10

r is the number of digits we can choose and it is equal to 4.

Number of possible 4 digit codes

= 10^4 = 100000