In the given Venn diagram, ‘Group A’ represents those who can speak 'English’, ‘Group B’ represents those who can speak ‘Hindi’, and ‘Group C’ represents those who can speak ‘Marathi’. The numbers given in the diagram represent the number of persons in that particular category.

How many persons can speak exactly two languages?

18

‘Group A’ represents those who can speak 'English’,

‘Group B’ represents those who can speak ‘Hindi’, 

‘Group C’ represents those who can speak ‘Marathi’.

Step 1 ) Look at the figure of  all circles

Step 2) Look at  number given in Exactly two languages speaking

Step 3) By visual observations we conclude that (5 +2 +11= 18 )  is the number which represents persons can speak exactly two languages