document.write( "Question 834691: Hi there, I think this goes here.\r
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document.write( "I have this word problem and I can't seem to wrap my head around it.\r
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document.write( "300 people attend an interview
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document.write( "100 had mobile phones (x)
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document.write( "70 had Passports (y)
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document.write( "140 had drivers licenses (z)\r
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document.write( "40 had x+y
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document.write( "30 had y+z
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document.write( "60 had x+z
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document.write( "10 had x+y+z\r
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document.write( "How many had none?\r
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document.write( "any help with this would be awesome! Thanks! \n" );
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Algebra.Com's Answer #503152 by jim_thompson5910(35256)![]() ![]() ![]() You can put this solution on YOUR website! A venn diagram really helps you visualize what is going on. So start off by drawing 3 overlapping circles inside a rectangle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "10 had x+y+z (aka 10 had all 3). Keep this in mind for the next parts. This value goes in the very center of the 3 overlapping circles.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "60 had x+z. So this means that 60-10 = 50 had only x and z but not y. Notice how we took out the people who had all 3 to make sure of this. This number 50 goes in the region between X and Z (but NOT in any region where Y is overlapping).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Similarly, 30 had y+z, so 30-10 = 20 had only y and z but not x. The number 30 goes in the region between Y and Z (but NOT x). Also, 40 had x+y which means 40-10 = 30 had only x and y but not z. Write the number 40 in the region between X and Y (but not z)\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now we must fill out the rest of the circular regions of the venn diagram. In the x circle for instance, all of the numbers must add to 100 (since there are 100 people who are in region x), so\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + 50 + 10 + 30 = 100\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + 90 = 100\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 100 - 90\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 10\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The other values are found the same way\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y + 30 + 10 + 20 = 70\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y + 60 = 70\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 70 - 60\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 10\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "z + 50 + 10 + 20 = 140\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "z + 80 = 140\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "z = 140 - 80\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "z = 60\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Finally, we add up all the values in the circular regions (but not outside the 3 circles) to get\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "10+30+10+50+10+20+60 = 190\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This means that there are 190 people who...\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "a) have just one thing x, y or z\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "b) have 2 things (x+y, x+z, y+z)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "OR\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "c) have all 3 things (x+y+z)\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So there are 300 - 190 = 110 people who have none of these 3 things.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Here is what the venn diagram would look like:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " ![]() |