You need a -digit passcode to unlock a lock .
If you know that :
, One of the numbers is correct and in the right place.
, There is no correct number here.
, There are two correct numbers but they are in the wrong place.
, There is one correct number but it is in the wrong place.
, There is one correct number but it is in the wrong place.
Then , what is the -digit passcode ?
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
From clue (2), we know that there is no 5 in the number. Then clue (3) tells us that 1 and 7 are both in the passcode. Now, using clue (1), this means that the passcode is either 7 4 1 or 7 1 8 . Either clue (4) or clue (5) -- we only need one of them -- tells us that 7 1 8 is indeed the correct code.