In a code language, 'please come over' is written as 'bnq tra mns', 'game is over' is written as 'din mns piz', 'come in please' is written as 'tra bnq pvc'. What is the code for the word 'in' in this language?

Let's isolate the code for each word by comparing the statements:
'please come over' = 'bnq tra mns'

'game is over' = 'din mns piz'

'come in please' = 'tra bnq pvc'

Comparing (1) and (2): 'over' is common, and the common code is 'mns'. So, over = mns.

Comparing (1) and (3): 'please' and 'come' are common, and the common codes are 'bnq' and 'tra'.

Now looking at statement (3) 'come in please' = 'tra bnq pvc':
Since 'come' and 'please' occupy the codes 'tra' and 'bnq' (in any order), the remaining word in this statement is 'in', and the remaining code is 'pvc'.

Thus, the code for 'in' is 'pvc'.