document.write( "Question 1078665: A survey of 100 students at New England College showed the following:
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document.write( "45 take English.
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document.write( "47 take history.
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document.write( "37 take language.
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document.write( "13 take English and history.
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document.write( "17 take English and language.
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document.write( "19 take history and language.
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document.write( "7 take all three.
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document.write( "How many students do the following? (See Example 6.)
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document.write( "(a) Take history but neither of the other two?
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document.write( "(b) Take English and history but not language?
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document.write( "(c) Take none of the three?
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document.write( "(d) Take just one of the three?
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document.write( "(e) Take exactly two of the three?
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document.write( "(f) Do not take language?
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Algebra.Com's Answer #693236 by ikleyn(52878) You can put this solution on YOUR website! A survey of 100 students at New England College showed the following: \n" ); document.write( "45 take English. \n" ); document.write( "47 take history. \n" ); document.write( "37 take language. \n" ); document.write( "13 take English and history. \n" ); document.write( "17 take English and language. \n" ); document.write( "19 take history and language. \n" ); document.write( "7 take all three. \n" ); document.write( "How many students do the following? (See Example 6.) \n" ); document.write( "~~~~~~~~~~~~~~~~~~\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \r\n" ); document.write( "Let E = the set of students learning English, and let n(E)= 45 be the number of elements in this set.\r\n" ); document.write( "\r\n" ); document.write( "Let H = the set of students learning History, and let n(H)= 47 be the number of elements in this set.\r\n" ); document.write( "\r\n" ); document.write( "Let L = the set of students learning Language, and let n(L)= 37 be the number of elements in this set.\r\n" ); document.write( "\r\n" ); document.write( "Let EH = the intersection of E and H, and let n(EH)= 13 be the number of elements in this set.\r\n" ); document.write( "\r\n" ); document.write( "Let EL = the intersection of E and L, and let n(EL)= 17 be the number of elements in this set.\r\n" ); document.write( "\r\n" ); document.write( "Let HL = the intersection of H and L, and let n(EL)= 19 be the number of elements in this set.\r\n" ); document.write( "\r\n" ); document.write( "Let EHL = the intersection of E, H and L, and let n(EHL)= 7 be the number of elements in this set.\r\n" ); document.write( "\r \n" ); document.write( "\n" ); document.write( " After introducing these notations, we are ready to solve the problem EASILY.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \r\n" ); document.write( "(a) Take history but neither of the other two?\r\n" ); document.write( " \r\n" ); document.write( " = n(H) - n(EH) - n(HL) + n(EHL) = 47 - 13 - 19 + 7 = 22.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "(b) Take English and history but not language?\r\n" ); document.write( " \r\n" ); document.write( " = n(EH) - n(EHL) = 13 - 7 = 6.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "(c) Take none of the three?\r\n" ); document.write( " \r\n" ); document.write( " = 100 - [n(E) + n(H) + n(L) - N(EH) - n(HL) - n(EL) + n(EHL)] = calculate it on your own: simply substitute data\r\n" ); document.write( "\r\n" ); document.write( " (What you see in BRACKETS is the number of those who takes at least one subject)\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "(d) Take just one of the three?\r\n" ); document.write( " \r\n" ); document.write( " = [n(E)-n(EH)-n(EL)+n(EHL)] + [n(L)-n(EL)-n(HL)+n(EHL)] + [n(H)-n(EH)-n(HL)+n(EHL)]] = calculate it on your own: simply substitute data\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "(e) Take exactly two of the three?\r\n" ); document.write( " \r\n" ); document.write( " = [n(EH) - n(EHL)] + [n(HL) - n(EHL)] + [n(EL) - n(EHL)] = calculate it on your own: simply substitute data\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "(f) Do not take language?\r\n" ); document.write( " \r\n" ); document.write( " = 100 - n(L) = 100 - 37 = 63.\r\n" ); document.write( "\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "See the lessons\r \n" ); document.write( "\n" ); document.write( " - Counting elements in sub-sets of a given finite set\r \n" ); document.write( "\n" ); document.write( " - Advanced problems on counting elements in sub-sets of a given finite set\r \n" ); document.write( "\n" ); document.write( "in this site.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r \n" ); document.write( "\n" ); document.write( " - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The referred lessons are the part of this online textbook under the topic \n" ); document.write( "\"Miscellaneous word problems\".\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |