SSAT Middle Level Math : How to use a Venn Diagram

Study concepts, example questions & explanations for SSAT Middle Level Math

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Example Questions

Example Question #11 : How To Use A Venn Diagram

Vt custom venn series ssat middle

The above Venn diagram represents the total number of respondents from a survey administered in \(\displaystyle 2014\). Respondents were categorized into only group \(\displaystyle x\), only group \(\displaystyle y\) or both of the groups. 

What fraction of the respondents were categorized into both groups? 

Possible Answers:

\(\displaystyle \frac{12}{10}\)

\(\displaystyle \frac{3}{25}\)

\(\displaystyle \frac{6}{100}\)

\(\displaystyle \frac{12}{50}\)

\(\displaystyle \frac{3}{50}\)

Correct answer:

\(\displaystyle \frac{3}{25}\)

Explanation:

Since the information provided in the Venn diagram represents percentages, convert the quantity in the common portion of the diagram from a percentage to a fraction. To convert a percentage to a fraction, divide the percentage by a divisor of \(\displaystyle 100\), then simplify the fraction if possible. 

Common portion is equal to \(\displaystyle 12\%\). Therefore, the solution is:

 

\(\displaystyle 12\div100=\frac{12}{100}=\frac{12\div 2}{100\div 2}=\frac{6}{50}=\frac{6\div 2}{50\div 2}=\frac{3}{25}\)

Example Question #12 : How To Use A Venn Diagram

Vt custom venn series ssat middle

Ms. Dunn gave her class a survey to find out which states her student's have visited. Ms. Dunn was surprised to find that all of her student's had visited either New York City or Texas, and some of her student's had visited both locations. 

The above Venn diagram represents the percentage of students who have visited only NYC, only Texas, and those who have visited both locations. 

What percentage of the students have visited both NYC and Texas? 

Possible Answers:

\(\displaystyle 78\%\)

\(\displaystyle 22\%\)

\(\displaystyle 28\%\)

\(\displaystyle 14\%\)

\(\displaystyle 38\%\)

Correct answer:

\(\displaystyle 22\%\)

Explanation:

The common portion of this Venn diagram represents the percentage of respondents that were classified into both groups. In order to calculate the percentage that represents how many students have visted both NYC and Texas, first find the sum of group \(\displaystyle NYC\) and group \(\displaystyle TX\). Then subtract that quantity from \(\displaystyle 100\%\).

The solution is: 

\(\displaystyle 46+32=78\)

\(\displaystyle 100-78=22\)

Example Question #13 : How To Use A Venn Diagram

Vt custom venn series ssat middle

Ms. Dunn gave her class a survey to find out which states her student's have visited. Ms. Dunn was surprised to find that all of her student's had visited either New York City or Texas, and some of her student's had visited both locations. 

The above Venn diagram represents the percentage of students who have visited only NYC, only Texas, and those who have visited both locations. 

What ratio represents the number of students that have gone only to NYC, in comparison to the rest of the class? 

Possible Answers:

\(\displaystyle 42:100\)

\(\displaystyle 23:39\)

\(\displaystyle 23:50\)

\(\displaystyle 4:6\)

\(\displaystyle 46:78\)

Correct answer:

\(\displaystyle 23:50\)

Explanation:

Since \(\displaystyle 46\%\) of Ms. Dunn's class have visited only NYC, \(\displaystyle 46\) out of every \(\displaystyle 100\) students must have only visited NYC. This can be represented by the ratio \(\displaystyle 46:100\); however, this ratio does not appear as an answer choice, so we must reduce this ratio by dividing each part by their greatest common divisor. 

The solution is:

\(\displaystyle 46:100=46\div2:100\div2=23:50\)


Example Question #14 : How To Use A Venn Diagram

Vt custom venn series ssat middle

Kayla used a popular social media website to survey her friends' hobbies. All of her friends either play sports or enjoy playing video games, and some of her friends do both. 

What fraction of her friends only play sports? 

Possible Answers:

\(\displaystyle \frac{1}{2}\)

\(\displaystyle \frac{3}{10}\)

\(\displaystyle \frac{2}{10}\)

\(\displaystyle \frac{3}{5}\)

\(\displaystyle \frac{1}{5}\)

Correct answer:

\(\displaystyle \frac{1}{2}\)

Explanation:

In order to calculate the fraction of Kayla's friends who only play sport, first find the sum of the common portion and video game portion of the Venn diagram. Then subtract that sum from \(\displaystyle 1\) whole. 

The solution is: 

\(\displaystyle \frac{3}{10}+\frac{2}{10}=\frac{5}{10}\)

Note: \(\displaystyle \frac{10}{10}=1\)

Thus, \(\displaystyle \frac{10}{10}-\frac{5}{10}=\frac{5}{10}=\frac{5\div 5}{10\div 5}=\frac{1}{2}\)

This means that half of Kayla's friends only play sports. 

Example Question #15 : How To Use A Venn Diagram

Vt custom venn series ssat middle

Kayla used a popular social media website to survey her friends' hobbies. All of her friends either play sports or enjoy playing video games, and some of her friends do both.

What percentage of Kayla's friends play sports and video games?

Possible Answers:

\(\displaystyle 30\%\)

\(\displaystyle 15\%\)

\(\displaystyle 20\%\)

\(\displaystyle 25\%\)

\(\displaystyle 50\%\)

Correct answer:

\(\displaystyle 30\%\)

Explanation:

In order to solve this problem, identify that the common portion of this Venn diagram represents Kayla's friends who play sports and video games. Since \(\displaystyle \frac{3}{10}\) of her friends play sports and video games, convert this fraction to a percent.

The solution is:

\(\displaystyle \frac{3}{10}=\frac{3\times 10}{10\times 10}=\frac{30}{100}=30\%\)


Note: the most efficient way to convert this fraction to a percent is to find an equivalent fraction to \(\displaystyle \frac{3}{10}\) with a denominator of \(\displaystyle 100\)

Example Question #26 : Venn Diagrams

Vt custom venn series ssat middle

The above Venn diagram represents the total number of respondents from a survey administered in \(\displaystyle 2014\). Respondents were categorized into only group \(\displaystyle x\), only group \(\displaystyle y\) or both of the groups. 

What percentage of respondents were categorized into only group \(\displaystyle y?\)

Possible Answers:

\(\displaystyle 49\%\)

\(\displaystyle 27\%\)

\(\displaystyle 39\%\)

\(\displaystyle 29\%\)

\(\displaystyle 63\%\)

Correct answer:

\(\displaystyle 49\%\)

Explanation:

To find the missing quantity for category \(\displaystyle y\), first calculate the sum from the common portion of the Venn diagram and category \(\displaystyle x\). Then, subtract that sum from \(\displaystyle 100\%\) , because the total percentage of respondents must equal \(\displaystyle 100\%\)

The algebraic solution is:

\(\displaystyle 39 +12=51\)

\(\displaystyle 100-51=49\)

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