Answer:
3/16 or 0.1875
Step-by-step explanation:
Since she remembers the first two digits, she only has to guess the last two digits. If both digits are greater than 5, there are 4 possible alternatives for each digit (6, 7, 8 or 9).
In three tries, the probability that she will get it right is:
The probability she will get access to her account is 3/16 or 0.1875.