In the given diagram, the shapes indicate the categories of persons. The numbers given in the different segments represent the number of persons in that category.

How many tennis players are either swimmers or rich persons but NOT both?

30

Step 1 ) Look at the figure of shapes given with identical names

Step 2) Look at  number given in the figure as tennis players are either swimmers or rich persons but NOT both

Step 3) By visual observations we conclude that (9 + 5 + 6 + 10 = 20) is the number which represents tennis players are either swimmers or rich persons but NOT both