Log in! (forgot password)
Username: Password:
Back Mystery Man Random ??? Next Bugs Eye
All Puzzles / Logical /

Cracking the Safe

You are to open a safe without knowing the combination. Beginning with the dial set at zero, the dial must be turned counter-clockwise to the first combination number, (then clockwise back to zero), and clockwise to the second combination number, (then counter-clockwise back to zero), and counter-clockwise again to the third and final number, where upon the door shall immediately spring open. There are 40 numbers on the dial, including the zero.

Without knowing the combination numbers, what is the maximum number of trials required to open the safe (one trial equals one attempt to dial a full three-number combination)?

Bookmark and Share
(Show)
(Show)
People who liked this also liked: Liar, Liar | Time To Fuse | Greatest Area |

Discussion

comments with spoilers hidden | Show All
folcklord about 1 month ago
folcklord about 1 month ago
buy accutane 896789 buy xanax pmoeg acomplia 43794 metoprolol 25 mg 9915 ultram >:]
folcklord about 1 month ago
kuleshs about 1 month ago
ultram :OOO accutane online 921589 ativan =-) buy ultram 90563 buy prednisone =-OOO
kuleshs about 1 month ago
kuleshs about 1 month ago
veggie 4 months ago

This should be a math problem, not a logic problem.

pkandel about 1 year ago

The answer/explanation given is definitely wrong, as the riddle itself specifies that “one trial equals one attempt to dial a full three-number combination”—meaning that each individual 3rd number tried counts as another full attempt.

d4m45t4 about 1 year ago contains spoiler (show)
ben037 about 1 year ago

this is wrong, the answer would be 40 permute 3, which is equal to 4040-30. the answer is actually 59,280

abominable puha about 1 year ago

But for the final number you are effectively testing all the numbers on the dial. If there was no test on the final number, however it is done, the lock won’t ever open. So 64000 is correct.

kash about 1 year ago contains spoiler (show)
weekendlush about 1 year ago contains spoiler (show)
valentin about 1 year ago

@adwootton
the question asks for the “maximum number of trials.” So the answer is fully correct.

adwootton@gmail.com about 1 year ago contains spoiler (show)