Question

The Venn Diagram represents a group of children who swam (left circle) and built sandcastles (right circle) at the beach.

Answer 1

Notice that 6 children went swimming only,
and 15 other children went swimming and build sandcastles.

So that's 21 children that went swimming.

So the proportion of swimmers (6 and 15) to the total number of children (6, 15 and 4) at the beach that day is\[\large\rm P(S)=\frac{6+15}{6+15+4}=\frac{21}{25}=0.84\]

Answer 2

Hopefully you can use this information to figure out some of the other ones.