document.write( "Question 1176466: The University of Ballygobackwards has three colleges:
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document.write( "- the College of Science, which has 19 staff, 5 of whom are female;
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document.write( "- the College of Engineering, which has 6 staff, 4 of whom are female;
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document.write( "- and the College of Arts, which has 18 staff, 8 of whom are female.\r
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document.write( "Each college has a Dean, who is chosen from the staff in that college.\r
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document.write( "a)What is the total number of ways these three Deans can be chosen?
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document.write( "b)How many ways can three Deans be chosen, so that at least one of them is female? \n" );
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Algebra.Com's Answer #803517 by ikleyn(52908) You can put this solution on YOUR website! . \n" ); document.write( "The University of Ballygobackwards has three colleges: \n" ); document.write( "- the College of Science, which has 19 staff, 5 of whom are female; \n" ); document.write( "- the College of Engineering, which has 6 staff, 4 of whom are female; \n" ); document.write( "- and the College of Arts, which has 18 staff, 8 of whom are female. \n" ); document.write( "Each college has a Dean, who is chosen from the staff in that college. \n" ); document.write( "a) What is the total number of ways these three Deans can be chosen? \n" ); document.write( "b) How many ways can three Deans be chosen, so that at least one of them is female? \n" ); document.write( "~~~~~~~~~~~~~\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " The post contains many words and seems to be a complicated problem, from the first glance.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " But actually, it is EXTREMELY simple.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \r\n" ); document.write( "(a) For the 1st college, there are 19 choices;\r\n" ); document.write( "\r\n" ); document.write( " For the 2nd college, there are 6 choices;\r\n" ); document.write( "\r\n" ); document.write( " For the 3rd college, there are 18 choices.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( " These choices are independent, since we choose in different / (separate) sets.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( " THEREFORE, the total number of triples of the three Deans is the product 19*6*18 = 2052. ANSWER\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( " (according to the Fundamental counting principle).\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "(b) In this part, we should subtract from the total number of cases 2052 of the part (a)\r\n" ); document.write( "\r\n" ); document.write( " the number of cases (19-5)*(6-4)*(18-8) = 13*2*10 = 260, when all the three Deans are men.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( " So, the answer is 2052 - 260 = 1792.\r\n" ); document.write( "\r \n" ); document.write( "\n" ); document.write( "Solved, answered, explained and completed.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |