A code lock cipher is a sequence of five characters, each of which is a digit from 1 to 4. How many different

A code lock cipher is a sequence of five characters, each of which is a digit from 1 to 4. How many different variants of the cipher can be set if it is known that the digit 1 can occur exactly two times, and each of the other valid digits can occur in the cipher any the number of times or not to meet at all?

1. First, you need to find a finite number of the total number of ways to put two odnerki on five positions.
Decision:
5 * 4/2 = 5 * 2 = 10 (ways);

2. We have determined the quantity, so the next step will be to put any number on the remaining positions.
Decision:
3 ^ 3 = 27 (ways);

3. Let’s calculate the total number of codes.
Decision:
10 * 27 = 270 (ways);

Answer: There are 270 ways.