In a certain code language, '479' means 'fruit is sweet';
'248' means 'very sweet voice' and
'637' means 'eat fruit daily'.
Which digit stands for 'is' in that code ?
In the first and second statements, the common code digit is '4' and the common word is 'sweet'.
So, '4' means 'sweet'.
In the first and third statements, the common code digit is '7' and the common word is 'fruit'.
So, '7' means 'fruit'.
Thus, in the first statement '9' means 'is'.