document.write( "Question 126497: Please show me how to solve this problem ( it was a homework problem (1 complete problem) and I didn't know where to start). thanks!\r
\n" ); document.write( "\n" ); document.write( "200 Students\r
\n" ); document.write( "\n" ); document.write( "70 Students take English class
\n" ); document.write( "54 Students take Math class
\n" ); document.write( "45 Students take Social Studies
\n" ); document.write( "28 Students take English and Math
\n" ); document.write( "19 Students take English and Scial Studies
\n" ); document.write( "15 Students take Math and Scial Studies
\n" ); document.write( "10 Students take English, Math and Social Studies\r
\n" ); document.write( "\n" ); document.write( "1.) How many students take English
\n" ); document.write( "2.) How many Students take math only
\n" ); document.write( "3.) How many Students take English, social studies but not math
\n" ); document.write( "4.) How many students take math and social studies but not English class
\n" ); document.write( "5.) How many do not take any class.
\n" ); document.write( "

Algebra.Com's Answer #92700 by marcsam823(57)\"\" \"About 
You can put this solution on YOUR website!
Since this problem contains several elements that are more easily tracked with a picture, I find the easiest way to solve it is with a Venn Diagram. Venn Diagrams are basically a series of overlapping circles that allow you to see all at once how your data relates. I can't draw Venn diagrams on this site, but if you'd like to learn more about them, go this site:\r
\n" ); document.write( "\n" ); document.write( "http://en.wikipedia.org/wiki/Venn_diagram and click the Examples hyperlink.\r
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\n" ); document.write( "\n" ); document.write( "Question 1)
\n" ); document.write( "We are given that a total of 70 students take English class. These students can be divided into 4 groups:
\n" ); document.write( "a = Students who take English, Math and Social Studies
\n" ); document.write( "b = Students who take English and Social Studies only
\n" ); document.write( "c = Students who take English and Math only
\n" ); document.write( "d = Students who take English only
\n" ); document.write( "a + b + c + d = 70 = Total students taking English \r
\n" ); document.write( "\n" ); document.write( "1. The problem gives us \"a+=+10\" students who take all 3 classes. This is a good start, because it will help us solve for b and c \r
\n" ); document.write( "\n" ); document.write( "2. Solve for b:
\n" ); document.write( "The problem also tells us that 19 students take English and Social Studies. This can be a little confusing because this 19 also includes the 10 that are taking Math as well.
\n" ); document.write( "Therefore: \"19+-+10+=+b+=+9\" students taking English and Social Studies ONLY.\r
\n" ); document.write( "\n" ); document.write( "3. Solve for c:
\n" ); document.write( "Similarly, we are given that 28 students are taking English and Math Therefore: \"28+-+10+=+c+=+18\" students taking English and Math ONLY.\r
\n" ); document.write( "\n" ); document.write( "4. Now we can solve for d, students who take English only:
\n" ); document.write( "\"a+%2B+b+%2B+c+%2B+d+=+70\"
\n" ); document.write( "\"10+%2B+9+%2B+18+%2B+d+=+70\"
\n" ); document.write( "\"37+%2B+d+=+70\"
\n" ); document.write( "\"d+=+33\"
\n" ); document.write( "33 students take English only.\r
\n" ); document.write( "\n" ); document.write( "Question 2)
\n" ); document.write( "We are given that a total of 54 students take math class. These students can be divided into 4 groups:
\n" ); document.write( "a = Students who take Math, English and Social Studies
\n" ); document.write( "c = Students who take Math and English only
\n" ); document.write( "e = Students who take Math and Social Studies only
\n" ); document.write( "f = Students who take Math only\r
\n" ); document.write( "\n" ); document.write( "a + c + e + f = 54 = Total students taking Math\r
\n" ); document.write( "\n" ); document.write( "Notice from question 1) we already have values for a and c so let's substitute:
\n" ); document.write( "\"10+%2B+18+%2B+e+%2B+f+=+54\",
\n" ); document.write( "so we don't have to do as much work for this part of the problem.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "1. Solve for e:
\n" ); document.write( "The problem also tells us that 15 students take Math and Social Studies. This can be a little confusing because this 15 also includes the 10 that are taking English as well.
\n" ); document.write( "Therefore: \"15+-+10+=+e+=+5\" students taking Math and Social Studies ONLY.\r
\n" ); document.write( "\n" ); document.write( "2. Now we can solve for f, students who take Math only.
\n" ); document.write( "\"a+%2B+c+%2B+e+%2B+f+=+54\"
\n" ); document.write( "\"10+%2B+18+%2B+5+%2B+f+=+54\"
\n" ); document.write( "\"33+%2B+f+=+54\"
\n" ); document.write( "\"f+=+21\"
\n" ); document.write( "21 students take Math only.\r
\n" ); document.write( "\n" ); document.write( "Question 3)
\n" ); document.write( "We've already done the work for this one! The total number of students who take English and Social Studies only is 9. (Our b variable from question 1)\r
\n" ); document.write( "\n" ); document.write( "Question 4)
\n" ); document.write( "We've done this one too! The total number of students who take math and social studies only is 5 (Our e variable from Question 2)\r
\n" ); document.write( "\n" ); document.write( "Question 5)
\n" ); document.write( "In order to find how many students are not taking classes we need to find the total number students who ARE.
\n" ); document.write( "We have all the elements we need except for one:
\n" ); document.write( "a = students take all three classes = 10
\n" ); document.write( "b = students taking English and Social Studies DISABLED_event_only= 9
\n" ); document.write( "c = students taking English and Math DISABLED_event_only= 18
\n" ); document.write( "d = students taking English DISABLED_event_only= 33
\n" ); document.write( "e = students taking Math and Social Studies DISABLED_event_only= 5
\n" ); document.write( "f = students taking Math DISABLED_event_only= 21
\n" ); document.write( "g = students taking Social Studies DISABLED_event_only= ???\r
\n" ); document.write( "\n" ); document.write( "1. We need to find a value for g:
\n" ); document.write( "We are told that a total of 45 are taking Social studies. This includes:
\n" ); document.write( "a = 10 = students taking all three classes
\n" ); document.write( "b = 9 = students taking Social Studies and English only
\n" ); document.write( "e = 5 = students taking Social studies and Math only
\n" ); document.write( "g = ?\r
\n" ); document.write( "\n" ); document.write( "2. Solve for g:
\n" ); document.write( "\"a+%2B+b+%2B+e+%2B+g+=+45\"
\n" ); document.write( "\"10+%2B+9+%2B+5+%2B+g+=+45\"
\n" ); document.write( "\"24+%2B+g+=+45\"
\n" ); document.write( "\"g+=+21\"
\n" ); document.write( "21 students take Social Studies only\r
\n" ); document.write( "\n" ); document.write( "3. Subtract from total student body of 200:
\n" ); document.write( "\"200+-+%28a+%2B+b+%2B+c+%2B+d+%2B+e+%2B+f+%2B+g%29\" = Students not taking a class
\n" ); document.write( "\"200+-+%2810+%2B+9+%2B+18+%2B+33+%2B+5+%2B+21+%2B+21%29\" =
\n" ); document.write( "\"200+-+117+=+83\"
\n" ); document.write( "83 students do not take English, Math or Social Studies. \r
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\n" ); document.write( "\n" ); document.write( "Just a Reminder:
\n" ); document.write( " A Venn diagram would have made this problem a lot easier. You would simply draw 3 overlapping circles. Label one \"Math\", one \"English\" and one \"Social Studies\". Each section created by an overlap is equal to one of the letters we used (there should be 7, a through g). To keep track of the total number of groups of students simply count the number of sections and label each with a letter.
\n" ); document.write( "a) Sections where no overlap occurs are for those students enrolled in one class only (there will be three sections like this)
\n" ); document.write( "b) Sections where two of the circles overlap are for those students who are enrolled in two classes (there will be three of these)
\n" ); document.write( "c) There will be one section where all three circles overlap for the 10 students taking all three classes.
\n" ); document.write( "In math, it is always easier to have a picture of your problem handy!\r
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