Expert: Lynn Houston - 2/26/2009

Question
The following venn diagram is part of my daughter's homework:

Mr. Russo took a survey of fifth graders' favorite dessers.
65 children liked cake the best.
37 children liked ice cream the best.
6 children did not like cake or ice cream the best.
How many children liked both cake and ice cream the best?

Maybe I am missing something, but don't you need to know how many students are in the class to answer this question?

Answer
You already do.  If there are 65 that like cake, 37 that like ice cream and 6 that like neither, if these are the only desserts, then there are 108 kids in the fifth grade.  What you cannot do is determine how many kids like both cake and ice cream best.