Solve the following problem by representing it in a Venn diagram.
At a children's party, the children are asked their preference regarding the flavor of ice cream,
obtaining the following results: 9 want chocolate, vanilla and strawberry; 12 strawberry and
vanilla, 13 chocolate and strawberry, 15 chocolate and vanilla, 18 strawberry, 26 vanilla, 29
chocolate, 8 other flavors.
a) How many children were at the party?
b) How many only want to try a single flavor?
c) How many children do not want vanilla?