In a certain coding system, 'displaying home excellence' is

Solution

I. 'displaying home excellence' is coded as 'gh qw vb'.

II. 'historic commended home' is coded as 'kl fg qw'.

III. 'commended gold excellence' is coded as 'xc kl vb'.

After decoding the codes, we get:

From statement I and II, we get 'home' is coded as 'qw'.

From statement I and III, we get 'excellence' is coded as 'vb'.

From statement I alone, we get 'displaying' is coded as 'gh'.

From statement II and III, we get 'commended' is coded as 'kl'.

From statement II alone, we get 'historic' is coded as 'fg'.

From statement III alone, we get 'gold' is coded as 'xc'.
Therefore, 'displaying historic' is coded as 'fg gh'.