Test #1 Blue Book Math Problem?

Test Preparation
1

<p>The problem is from the third section #5</p>

<p>The Venn Diagram above shows the distribution of 30 science students who studied butterflies, grasshoppers, both or neither. What percent of the students studied butterflies only?</p>

<p>The link to the venn diagram is below:</p>

<p><a href="https://docs.google.com/viewer?a=v&q=cache:FaIkkb6zQ40J:mrfuguet.wikispaces.com/file/view/SAT%2BTest%2B1%2BPart%2B1.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESjQytTypDk3eWlAfvzqj8TJcOxsHhGHU1JfCYrF6-n6kO6vInCpO8UD8cEYdvLUQBpBnCi1iKRpgWUtnnelNNT56MLoCwdslXIhmS50iJR-VysnrgNdjZmE4pjeylFMpqkKuzKD&sig=AHIEtbRb4p-iDvFufKnRgJxZD28dzOeRTw%5B/url%5D"&gt;https://docs.google.com/viewer?a=v&q=cache:FaIkkb6zQ40J:mrfuguet.wikispaces.com/file/view/SAT%2BTest%2B1%2BPart%2B1.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESjQytTypDk3eWlAfvzqj8TJcOxsHhGHU1JfCYrF6-n6kO6vInCpO8UD8cEYdvLUQBpBnCi1iKRpgWUtnnelNNT56MLoCwdslXIhmS50iJR-VysnrgNdjZmE4pjeylFMpqkKuzKD&sig=AHIEtbRb4p-iDvFufKnRgJxZD28dzOeRTw&lt;/a&gt;&lt;/p>

<p>I picked answer B because I figured you had to subtract the students who studied both butterflies and grasshoppers from the students who studied butterflies to find the students who studied only butterflies. I was wrong and the answer is C. I do not understand why.</p>

2

<p>The “3” in the bottom right hand corner studied neither.</p>

<p>The “3” in the overlap area studied both.</p>

<p>“9” studied B only.</p>

<p>“15” studied G only.</p>

<p>So the answer is 9/30 or 30%.</p>