The set that the shaded part of each Venn Diagram represents is $a^{\text{'}}\cup (A\cup C)$ . Find $a$

The set that the shaded part of each Venn Diagram represents is $B^{\text{'}}\cup {(A\cup a)}^{\text{'}}$. Find $a$.

For the Venn Diagram, describe the characteristics of only whales, of only fish, and those of both whales and fish. 

Explain how the diagram has helped with your descriptions and whether a different form could be more useful. 

Below is a table describing some characteristics of whale, fish and shrimp. Create a Venn Diagram that illustrates these characteristics. Make sure to choose an appropriate Universal Set. 

In a school cafeteria at lunchtime, $93$ students chose a soft drink and $47$ students chose bottled water. $25$ students chose both drinks. If each student chose one of these drinks, determine the total number of students in the cafeteria by drawing a Venn diagram.