sumana
A password to a certain database consists of digits that cannot be repeated. If the password is known to consist of at least 8 digits and it takes 12 seconds to try one combination, what is the amount of time, in minutes, necessary to guarantee access to database?
A. 8!/5
B. 8!/2
C. 8!
D. 10!/2
E. 5/2.10!
I think the question is flawed.
Let me chalk out the conditions according to the question's language.
Condition 1 - Password contains at least 8 digits
Condition 2 - All the digits of the password are different.
For both the conditions to be satisfied, there can be three cases.
Case 1 - 8 distinct digits. Bunuel has solved this part.
Case 2 - 9 distinct digits. This will be given by
\(10*9*8*.....*2\) = \(10!\)
To try each permutation 1/5 of a minute is needed.
Case 3 - 10 distinct digits. Same as Case 2.
So the worst case scenario for our "testing machine" will be
8 digits testing - No joy!
9 digits testing - No joy!
10 digits testing - exactly the last one tested turns out to be the match.
Bunuel Please see.
I may be overthinking too much about this!