PSAT Math : Venn Diagrams

Study concepts, example questions & explanations for PSAT Math

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Example Questions

Example Question #1 : Venn Diagrams

Venn_3

Giving the Venn diagram above, what is the sum of the numbers in the set ?

Possible Answers:

Correct answer:

Explanation:

The notation  stands for "A union C," which refers to everything that is in either set  or set .

When we add the numbers together, we get:

Example Question #11 : Venn Diagrams

In a class of senior high-school students,  have pet cats,  have pet dogs,  have both cats and dogs, and  have neither cats nor dogs. How many total students are in the class?

Possible Answers:

Correct answer:

Explanation:

A Venn diagram can help us determine the total number of students in the class.

First, we must calculate the number of students who have ONLY cats or ONLY dogs. First, for cats, 15 students have cats, and 5 students have both cats and dogs.

Ten students have only cats.

For dogs, 12 students have dogs, and 5 students have both cats and dogs.

Seven students have only dogs. 

Using this information, we can fill in the Venn diagram.

Venn_4

This diagram shows the 10 students with only cats, the 7 students with only dogs, the 5 students with both, and the 8 students with neither.  Adding up the numbers will give us the total number of students.

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