The given Venn diagram represents artists in a circus:

The triangle represents clowns, the circle represents acrobats, the rectangle represents males and the square represents ringmasters. The numbers given in the diagram represent the number of persons in that particular category.

How many male clowns are also ringmasters, but NOT acrobats?

17

The triangle represents clowns

The circle represents acrobats

The rectangle represents males 

The square represents ringmasters

Step 1 ) Look at the figure of  Circle , Triangle, Rectangle , Square

Step 2) Look at  number given male clowns are also ringmasters, but NOT acrobats  17

Step 3) By visual observations we conclude that 17  is the number which represents  male clowns are also ringmasters, but NOT acrobats