In Mixed letter coding type of questions, three or four complete messages are given in the coded language and the code for a particular word is asked. To analyse such codes, any two messages bearing a common word are picked up. The common code word will mean that word. Proceeding smilarly by picking up all possible combinations of two, the entire message can be analysed.
In a certain code, 'nee tim see' means 'how are you';
'ble nee see' means 'where are you',
what is the code for 'where' ?
In the first, and second statements, the common code words 'nee' and 'see' mean 'are' and 'you'.
So, in the second statement, the remaining code 'ble' means 'where'.