Answer:
10,080 eight-digit codes.
Explanation:
Given the date: 01/28/1996
Since there are 8 digits, the number of possible combinations = 8!
The following digits are repeated:
• Digit 1 = 2 times = 2!
,• Digit 9 = 2 times = 2!
Therefore, the number of eight-digit codes she could make using the digits in her birthday is:
[tex]\frac{8!}{2!2!}=\frac{8\times7\times6\times5\times4\times3\times2\times1}{2\times2}=\frac{40320}{4}=10,080[/tex]Hence 10,080 eight-digit codes can be formed.
