Re: I don't understand

Posted by

melkiy 4 Nov 2009 03:00

Because

1) There are 0 pairs of employees whose pin-codes are different at 1 position.

2) There are 0 pairs of employees whose pin-codes differ at 1 position.

3) There are 2 pairs of employees (1 and 2, 1 and 3) whose pin-codes differ at 3 positions

4) There is 1 pair of employees (2 and 3) whose pin-codes differ at all 4 positions.