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 code language, 'mok dan sil' means 'nice big house';
'fit kon dan' means 'house is good' and
'warn tir fit' means 'cost is high'.
Which word stands for 'good' in that language ?
In the first and second statements, the common code word is 'dan' and the common word is 'house'.
So, 'dan' means 'house'.
In the second and third statements, the common code word is 'fit'.
So 'fit' stands for 'is'.
Thus, in the seccond statement, 'kon' stands for 'good'.