ISEE Upper Level Math : How to use a Venn Diagram

Study concepts, example questions & explanations for ISEE Upper Level Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #1 : Data Analysis

Venn

 

Refer to the above Venn diagram.

Define universal set \displaystyle U = \mathbb{N}, the set of natural numbers.

Define sets \displaystyle A and \displaystyle B as follows:

\displaystyle A = \left \{ 1,5,9,13,17,21,... \right \}

\displaystyle B = \left \{ 2,5,8,11,14,17...\right \}

Which of the following numbers is an element of the set represented by the gray area in the diagram?

Possible Answers:

\displaystyle 105

\displaystyle 101

\displaystyle 103

\displaystyle 104

\displaystyle 102

Correct answer:

\displaystyle 104

Explanation:

The gray area represents the set of all elements that are in \displaystyle B but not in \displaystyle A.

\displaystyle B is the set of integers that, when divided by 3, yield remainder 2. Therefore, we can eliminate 102 and 105, both multiples of 3, and 103, which, when divided by 3, yields remainder 1.

\displaystyle A is the set of integers that, when divided by 4, yield remainder 1. Since we do not want an element from this set, we can eliminate 101, but not 104. 

104 is the correct choice.

Example Question #2 : Data Analysis

Venn

In the above Venn diagram, the universal set is defined as  \displaystyle U = \left \{ a, b, c, d, e, f, g, h\right \}. Each of the eight letters is placed in its correct region.

What is \displaystyle A \cap B ?

Possible Answers:

\displaystyle A \cap B = \left \{ b,d,e,g,h \right \}

\displaystyle A \cap B = \left \{ a,b,d,e,f,g,h \right \}

\displaystyle A \cap B = \left \{ b,c,d,e,g,h \right \}

\displaystyle A \cap B = \left \{ a,f \right \}

\displaystyle A \cap B = \left \{ a,c,f \right \}

Correct answer:

\displaystyle A \cap B = \left \{ a,f \right \}

Explanation:

\displaystyle A \cap B is the intersection of sets \displaystyle A and \displaystyle B - that is, the set of all elements of \displaystyle U that are elements of both \displaystyle A and \displaystyle B. We want all of the letters that fall in both circles, which from the diagram can be seen to be \displaystyle a and \displaystyle f. Therefore, 

\displaystyle A \cap B = \left \{ a,f \right \}

Example Question #3 : Data Analysis And Probability

Venn

In the above Venn diagram, the universal set is defined as  \displaystyle U = \left \{ a, b, c, d, e, f, g, h\right \}. Each of the eight letters is placed in its correct region. Which of the following is equal to \displaystyle \overline{A\cap B} ?

Possible Answers:

\displaystyle \overline{A\cap B} = \left \{ b,c,d,e,g,h\right \}

\displaystyle \overline{A\cap B} = \left \{ a,f\right \}

\displaystyle \overline{A\cap B} = \left \{ a,c,f\right \}

\displaystyle \overline{A\cap B} = \left \{ c\right \}

\displaystyle \overline{A\cap B} = \left \{ b,d,e,g,h\right \}

Correct answer:

\displaystyle \overline{A\cap B} = \left \{ b,c,d,e,g,h\right \}

Explanation:

\displaystyle \overline{A \cap B}  is the complement of \displaystyle A \cap B - the set of all elements in \displaystyle U not in \displaystyle A \cap B

\displaystyle A \cap B is the intersection of sets \displaystyle A and \displaystyle B - that is, the set of all elements of \displaystyle U that are elements of both \displaystyle A and \displaystyle B. Therefore, \displaystyle \overline{A \cap B} is the set of all elements that are not in both \displaystyle A and \displaystyle B, which can be seen from the diagram to be all elements except \displaystyle a and \displaystyle f. Therefore, 

\displaystyle \overline{A\cap B} = \left \{ b,c,d,e,g,h\right \}.

Example Question #4 : Data Analysis And Probability

Venn

In the above Venn diagram, the universal set is defined as  \displaystyle U = \left \{ a, b, c, d, e, f, g, h\right \}. Each of the eight letters is placed in its correct region. Which of the following is equal to \displaystyle \overline{A\cup B} ?

Possible Answers:

\displaystyle \overline{A\cup B} = \left \{ c\right \}

\displaystyle \overline{A\cup B} = \left \{ a,c,f\right \}

\displaystyle \overline{A\cup B} = \left \{ a,f\right \}

\displaystyle \overline{A\cup B} = \left \{ b,d,e,g,h\right \}

\displaystyle \overline{A\cup B} = \left \{ b,c,d,e,g,h\right \}

Correct answer:

\displaystyle \overline{A\cup B} = \left \{ c\right \}

Explanation:

\displaystyle \overline{A\cup B} is the complement of \displaystyle A\cup B - the set of all elements in \displaystyle U not in \displaystyle A\cup B.

\displaystyle A\cup B is the union of sets \displaystyle A and \displaystyle B - the set of all elements in either \displaystyle A or \displaystyle B. Therefore, \displaystyle \overline{A\cup B} is the set of all elements in neither \displaystyle A nor \displaystyle B, which can be seen from the diagram to be only one element - \displaystyle c. Therefore, 

\displaystyle \overline{A\cup B} = \left \{ c\right \}

Example Question #551 : Isee Upper Level (Grades 9 12) Mathematics Achievement

The following Venn diagram depicts the number of students who play hockey, football, and baseball. How many students play football and baseball?

Problem_9

Possible Answers:

\displaystyle 50

\displaystyle 6

\displaystyle 3

\displaystyle 53

Correct answer:

\displaystyle 6

Explanation:

The number of students who play football or baseball can by finding the summer of the number of students who play football alone, baseball alone, baseball and football, and all three sports.

\displaystyle 30+20+3+3=56

Example Question #2 : Data Analysis And Probability

A class of \displaystyle 30 students was asked whether they have cats, dogs, or both.The results are depicted in the following Venn diagram. How many students do not have a dog?

Question_5

Possible Answers:

\displaystyle 9

\displaystyle 19

 

\displaystyle 11

\displaystyle 21

Correct answer:

\displaystyle 19

 

Explanation:

First, calculate the number of students with a dog:
\displaystyle 9+2=11

Next, subtract the number of students with a dog from the total number of students.

\displaystyle 30-11=19

Learning Tools by Varsity Tutors