document.write( "Question 1194404: A survey of 130 pet owners yielded the following information: 47 own fish; 53 own a bird; 50 own a cat; 64 own a dog; 2 own all four; 11 own only fish; 14 own only a bird; 10 own fish and a bird; 21 own fish and a cat; 24 own a bird and a dog; 27 own a cat and a dog; 3 own fish, a bird, a cat, and no dog; 1 owns fish, a bird, a dog, and no cat; 9 own fish, a cat, a dog, and no bird; and 10 own a bird, a cat, a dog, and no fish. How many of the surveyed pet owners have no fish, no birds, no cats, and no dogs? (They own other types of pets.) \n" ); document.write( "
Algebra.Com's Answer #826612 by math_tutor2020(3817)![]() ![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "A = person owns a fish \n" ); document.write( "B = person owns a bird \n" ); document.write( "C = person owns a cat \n" ); document.write( "D = person owns a dog\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "There are 4 pets, so there are 2^4 = 16 different possibilities.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Here are the 16 possibilities
\n" ); document.write( "--------------------------------------------------------------------------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's draw out the Venn Diagram.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Start by drawing two ovals like so. Make sure they overlap. \n" ); document.write( " ![]() \n" ); document.write( "Create a mirror copy of those two ovals to have a total of four ovals. \n" ); document.write( " ![]() \n" ); document.write( "Then slide the ovals over until we get this \n" ); document.write( " ![]() \n" ); document.write( "It may seem like a bit of a mess, so be sure you can break apart the various ovals (or be able to spot the four ovals). \n" ); document.write( "This is why I recommend following these steps to slide the ovals over. \n" ); document.write( "Unfortunately we can't have the ovals separated or else we won't be able to form the overlapped regions needed.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Next, we'll add the 15 labels mentioned in the previous section above. The first label of \"none of the 4 pets mentioned\" is ignored for now, as it goes outside the four ovals. \n" ); document.write( " ![]() \n" ); document.write( "Color-coding things helps us separate the various regions (it may be easy to get lost) \n" ); document.write( " ![]() \n" ); document.write( "
\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Take note how something like region ABC is in ovals A, B and C at the same time. Region ABC is outside oval D. \n" ); document.write( "Similar logic applies to how the other regions are set up. \n" ); document.write( "The region outside the ovals represents people who own none of the four pets mentioned.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--------------------------------------------------------------------------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's fill out the Venn Diagram with numeric values.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "To do so, we'll need to use the given facts:
\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We start with statement 5, which says \"2 own all four\" \n" ); document.write( "This number goes inside the region labeled ABCD. \n" ); document.write( "In other words, this number goes in the region that is inside all four ovals.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now move onto statement 6. It says \"11 own only fish\", which means 11 goes in the region labeled \"A\". \n" ); document.write( "This is the region inside oval A, but outside any other oval.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now onto statement 7. It says \"14 own only a bird\", so we'll write \"14\" in region B. This is the region inside oval B, but outside any other oval.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's jump ahead to statement 12. \n" ); document.write( "It says \"3 own fish, a bird, a cat, and no dog\". \n" ); document.write( "We'll write the number 3 inside the region labeled \"ABC\". \n" ); document.write( "This is the region inside ovals A,B,C but outside oval D. \n" ); document.write( "To be more accurate, I'll write it off to the side since region ABC is very small. \n" ); document.write( "I'll be doing the same with regions ABD, AC and BD as well.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The next statement (statement 13) says \"1 owns fish, a bird, a dog, and no cat\" \n" ); document.write( "The number \"1\" goes with region ABD.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Up next is the statement \"9 own fish, a cat, a dog, and no bird\" (statement 14). It tells us that the number 9 goes inside region ACD.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Up next is the statement \"10 own a bird, a cat, a dog, and no fish\" (statement 15). \n" ); document.write( "It tells us that the number 10 goes inside region BCD.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Here's a mini recap so far: \n" ); document.write( "A = 11 \n" ); document.write( "B = 14 \n" ); document.write( "ABC = 3 \n" ); document.write( "ABD = 1 \n" ); document.write( "ACD = 9 \n" ); document.write( "BCD = 10 \n" ); document.write( "ABCD = 2 \n" ); document.write( "That takes care of 7 regions, so there are 16-7 = 9 more to go.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This is what your Venn Diagram should look like at this point (after filling in the proper regions) \n" ); document.write( " ![]() \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We'll move to statement 8 now. \n" ); document.write( "It says \"10 own fish and a bird\" \n" ); document.write( "Use a pen tool to highlight oval A and oval B as shown below. \n" ); document.write( " ![]() \n" ); document.write( "The two ovals highlighted overlap in this teardrop shaped region marked below \n" ); document.write( " ![]() \n" ); document.write( "Everything in this teardrop region is in oval A and oval B at the same time. The subregions involved in this teardrop are: \n" ); document.write( "Region AB \n" ); document.write( "Region ABC \n" ); document.write( "Region ABD \n" ); document.write( "Region ABCD \n" ); document.write( "Each of the four strings starts with \"AB\", and we either leave it as is, or we tack on various combos of C and/or D. \n" ); document.write( "This is a methodical way to list out all the possibilities of someone owning a fish and a bird (and possibly a cat and/or dog).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Algebraically we can form the equation \n" ); document.write( "AB+ABC+ABD+ABCD = 10 \n" ); document.write( "since 10 people own a fish and a bird (and possibly a cat and/or dog).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Be careful and try not to think about something like \"ABC\" as \"A*B*C\". \n" ); document.write( "ABC is one variable name, and not the product of three separate variables.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We'll apply the following substitutions \n" ); document.write( "ABC = 3 \n" ); document.write( "ABD = 1 \n" ); document.write( "ABCD = 2 \n" ); document.write( "to go from this \n" ); document.write( "AB+ABC+ABD+ABCD = 10 \n" ); document.write( "to this \n" ); document.write( "AB+3+1+2 = 10 \n" ); document.write( "and it solves to \n" ); document.write( "AB = 4 \n" ); document.write( "This says \"4 people have a fish and a bird, but not a cat and not a dog\". \n" ); document.write( "That was all for statement 8. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now onto statement 9. \n" ); document.write( "We'll have this equation \n" ); document.write( "AC+ABC+ACD+ABCD = 21 \n" ); document.write( "Each item on the left hand side has \"A\" and \"C\" in it somewhere. \n" ); document.write( "Plug in these items \n" ); document.write( "ABC = 3 \n" ); document.write( "ACD = 9 \n" ); document.write( "ABCD = 2 \n" ); document.write( "to go from this \n" ); document.write( "AC+ABC+ACD+ABCD = 21 \n" ); document.write( "to this \n" ); document.write( "AC+3+9+2 = 21 \n" ); document.write( "which solves to \n" ); document.write( "AC = 7 \n" ); document.write( "Therefore, 7 people have a fish and a cat, but none of the other two mentioned pets.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Onto statement 10. \n" ); document.write( "We'll have this equation \n" ); document.write( "BD+ABD+BCD+ABCD = 24 \n" ); document.write( "Each item on the left hand side has \"B\" and \"D\" in it somewhere. \n" ); document.write( "Plug in these items \n" ); document.write( "ABD = 1 \n" ); document.write( "BCD = 10 \n" ); document.write( "ABCD = 2 \n" ); document.write( "to go from this \n" ); document.write( "BD+ABD+BCD+ABCD = 24 \n" ); document.write( "to this \n" ); document.write( "BD+1+10+2 = 24 \n" ); document.write( "which solves to \n" ); document.write( "BD = 11 \n" ); document.write( "Therefore, 11 people have a bird and a dog, but none of the other two mentioned pets.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Onto statement 11. \n" ); document.write( "We'll have this equation \n" ); document.write( "CD+ACD+BCD+ABCD = 27 \n" ); document.write( "Each item on the left hand side has \"CD\" in it. \n" ); document.write( "Plug in these items \n" ); document.write( "ACD = 9 \n" ); document.write( "BCD = 10 \n" ); document.write( "ABCD = 2 \n" ); document.write( "to go from this \n" ); document.write( "CD+ACD+BCD+ABCD = 27 \n" ); document.write( "to this \n" ); document.write( "CD+9+10+2 = 27 \n" ); document.write( "which solves to \n" ); document.write( "CD = 6 \n" ); document.write( "Therefore, 6 people have a cat and a dog, but none of the other two mentioned pets.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's update that previous recap: \n" ); document.write( "ABCD = 2 \n" ); document.write( "A = 11 \n" ); document.write( "B = 14 \n" ); document.write( "ABC = 3 \n" ); document.write( "ABD = 1 \n" ); document.write( "ACD = 9 \n" ); document.write( "BCD = 10 \n" ); document.write( "AB = 4 \n" ); document.write( "AC = 7 \n" ); document.write( "BD = 11 \n" ); document.write( "CD = 6 \n" ); document.write( "The new items are in red.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--------------------------------------------------------------------------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Go back to the top to statement 1. \n" ); document.write( "47 people own a fish. Some of these 47 people own a fish only, while others may own exactly one other pet along with the fish, or two other pets along with the fish, or own all 4 pets mentioned.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "A = fish owners only \n" ); document.write( "AB = fish + bird \n" ); document.write( "AC = fish + cat \n" ); document.write( "AD = fish + dog \n" ); document.write( "ABC = fish + bird + cat \n" ); document.write( "ABD = fish + bird + dog \n" ); document.write( "ACD = fish + cat + dog \n" ); document.write( "ABCD = all four pets mentioned \n" ); document.write( "It may help to use your pen tool to circle all of oval A.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have the following values: \n" ); document.write( "A = 11 (given from statement 6) \n" ); document.write( "AB = 4 (solved earlier; see statement 8) \n" ); document.write( "AC = 7 (solved earlier; see statement 9) \n" ); document.write( "AD = unknown, we'll be solving for it soon \n" ); document.write( "ABC = 3 (solved earlier; see statement 12) \n" ); document.write( "ABD = 1 (solved earlier; see statement 13) \n" ); document.write( "ACD = 9 (solved earlier; see statement 14) \n" ); document.write( "ABCD = 2 (given; see statement 5)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "These values must add up to the 47 fish owners \n" ); document.write( "A+AB+AC+AD+ABC+ABD+ACD+ABCD = 47 \n" ); document.write( "11+4+7+AD+3+1+9+2 = 47 \n" ); document.write( "AD+37 = 47 \n" ); document.write( "AD = 47-37 \n" ); document.write( "AD = 10 \n" ); document.write( "There are 10 people who have a fish and a dog, but no other pet mentioned.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Move onto statement 2, which says \"53 own a bird\". \n" ); document.write( "We'll circle the regions that involve the letter B in some fashion, i.e. we'll circle all of oval B. \n" ); document.write( "B = bird owners only \n" ); document.write( "AB = fish + bird \n" ); document.write( "BC = bird + cat \n" ); document.write( "BD = bird + dog \n" ); document.write( "ABC = fish + bird + cat \n" ); document.write( "ABD = fish + bird + dog \n" ); document.write( "BCD = bird + cat + dog \n" ); document.write( "ABCD = all four pets mentioned\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We'll be using these values to help solve for variable BC \n" ); document.write( "B = 14 (given; see statement 7) \n" ); document.write( "AB = 4 (solved earlier; see statement 8) \n" ); document.write( "BD = 11 (solved earlier; see statement 10) \n" ); document.write( "ABC = 3 (solved earlier; see statement 12) \n" ); document.write( "ABD = 1 (solved earlier; see statement 13) \n" ); document.write( "BCD = 10 (solved earlier; see statement 15) \n" ); document.write( "ABCD = 2 (given; see statement 5)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So, \n" ); document.write( "B+AB+BC+BD+ABC+ABD+BCD+ABCD = 53 \n" ); document.write( "14+4+BC+11+3+1+10+2 = 53 \n" ); document.write( "BC = 8 \n" ); document.write( "There are 8 pet owners that have a bird and a cat, but no other pets mentioned.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now onto statement 3. \n" ); document.write( "Circle oval C, i.e. circle each region that involves C in some way \n" ); document.write( "C = cat only \n" ); document.write( "AC = fish and cat only \n" ); document.write( "BC = bird and cat only \n" ); document.write( "CD = cat and dog only \n" ); document.write( "ABC = fish + bird + cat \n" ); document.write( "ACD = fish + cat + dog \n" ); document.write( "BCD = bird + cat + dog \n" ); document.write( "ABCD = all four pets mentioned\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We have the following values: \n" ); document.write( "AC = 7 (solved earlier in statement 9) \n" ); document.write( "BC = 8 (solved earlier in statement 2) \n" ); document.write( "CD = 6 (solved earlier in statement 11) \n" ); document.write( "ABC = 3 (see statement 12) \n" ); document.write( "ACD = 9 (see statement 14) \n" ); document.write( "BCD = 10 (see statement 15) \n" ); document.write( "ABCD = 2 (see statement 5)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So, \n" ); document.write( "C+AC+BC+CD+ABC+ACD+BCD+ABCD = 50 \n" ); document.write( "C+7+8+6+3+9+10+2 = 50 \n" ); document.write( "C+45 = 50 \n" ); document.write( "C = 50-45 \n" ); document.write( "C = 5 \n" ); document.write( "There are 5 people who own a cat only (and none of the other three pets mentioned).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now onto the last statement left, which is statement 4. \n" ); document.write( "There are 64 people who own a dog which means, \n" ); document.write( "D+AD+BD+CD+ABD+ACD+BCD+ABCD = 64 \n" ); document.write( "D+10+11+6+1+9+10+2 = 64 \n" ); document.write( "D+49 = 64 \n" ); document.write( "D = 64-49 \n" ); document.write( "D = 15 \n" ); document.write( "There are 15 dog owners who do not have a fish, nor a bird, nor a cat.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--------------------------------------------------------------------------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Here's the complete summary of what we found \n" ); document.write( "A = 11 \n" ); document.write( "B = 14 \n" ); document.write( "C = 5 \n" ); document.write( "D = 15 \n" ); document.write( "AB = 4 \n" ); document.write( "AC = 7 \n" ); document.write( "AD = 10 \n" ); document.write( "BC = 8 \n" ); document.write( "BD = 11 \n" ); document.write( "CD = 6 \n" ); document.write( "ABC = 3 \n" ); document.write( "ABD = 1 \n" ); document.write( "ACD = 9 \n" ); document.write( "BCD = 10 \n" ); document.write( "ABCD = 2 \n" ); document.write( "This is what the completed Venn Diagram looks like \n" ); document.write( " ![]() \n" ); document.write( "The 14 outside of all of the ovals is the final answer and explained in the next two paragraphs.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Add up all of those values to find out how many people there are that own at least one of the four pets mentioned. \n" ); document.write( "A+B+C+D+AB+AC+AD+BC+BD+CD+ABC+ABD+ACD+BCD+ABCD \n" ); document.write( "11+14+5+15+4+7+10+8+11+6+3+1+9+10+2 \n" ); document.write( "116\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "There are 116 people who have at least one pet of the four pets mentioned. \n" ); document.write( "There are 130 people total. \n" ); document.write( "That must mean there are 130-116 = 14 people who do not have any of the four pets mentioned.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "--------------------------------------------------------------------------------------------------------------------------\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Final Answer: 14 \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " |