In the following Venn diagram, the square stands for 'Doctors', the circle stands for “Blood donators’, and the pentagon stands for ‘Women’, The given numbers represent the number of persons in that particular category.

How many women doctors are blood donators?

50

The square stands for 'Doctors'

The circle stands for “Blood donators’

The pentagon stands for ‘Women’

Step 1 ) Look at the figure of  ‘Women  ,Blood donators ,  Doctors

Step 2) Look at common  number between them  in all is 50

Step 3)  By visual representation we can conclude 50 is the number of women doctors are blood donators