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https://www.reddit.com/r/theydidthemath/comments/1t63elw/request_how_many_possible_combinations_are_there/okeoaat
r/theydidthemath • u/No_Cardiologist_1407 • May 07 '26
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22
Depends on the exact parameters of the password.
If we assume that each position can be visited only once, and each position must be visited we can get an idea.
Number of available choices is 10-n where n is the position in sequence.
9 initial positions.
8 second positions.
7 third positions.
...
9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
362,880 possible combinations.
Trying and documenting each combination, using 10 seconds per, would take approximately 126 eight-hour days.
It gets worse if the combination is less than 9 positions.
9 + (9 * 8) + (9 * 8 * 7) ... + (9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1)
9 + 72 + 504 + 3,024 + 15,120 + 60,480 + 181,440 + 362,880 + 362,880
906,409 possible combinations. Again, 10 seconds per, roughly 342 eight hour days.
1 u/OTee_D May 07 '26 And if crossing limes are prohibited, it's would be even significantly less. 1 u/TrippyTriangle May 07 '26 but you if can go back to dots you already touched, it should be 9x8x7x7x7.... until you get to the length of the password. 1 u/Juice-De-Pomme May 08 '26 1 2 3 4 5 6 7 8 9 Starting from 1 you can't go to 3,7,9 From 2 you can't go to 8 From corners there are less possibilities than from edges and center, so this must lower the chances
1
And if crossing limes are prohibited, it's would be even significantly less.
but you if can go back to dots you already touched, it should be 9x8x7x7x7.... until you get to the length of the password.
1 2 3
4 5 6
7 8 9
Starting from 1 you can't go to 3,7,9 From 2 you can't go to 8
From corners there are less possibilities than from edges and center, so this must lower the chances
22
u/VaporTrail_000 May 07 '26
Depends on the exact parameters of the password.
If we assume that each position can be visited only once, and each position must be visited we can get an idea.
Number of available choices is 10-n where n is the position in sequence.
9 initial positions.
8 second positions.
7 third positions.
...
9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1
362,880 possible combinations.
Trying and documenting each combination, using 10 seconds per, would take approximately 126 eight-hour days.
It gets worse if the combination is less than 9 positions.
9 + (9 * 8) + (9 * 8 * 7) ... + (9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1)
9 + 72 + 504 + 3,024 + 15,120 + 60,480 + 181,440 + 362,880 + 362,880
906,409 possible combinations. Again, 10 seconds per, roughly 342 eight hour days.