document.write( "Question 1124321: The names of four students are placed in a small box and two will be selected to represent the
\n" ); document.write( "school in an oratory contest. Let 1, 2, 3 and 4 denote the students. What is the probability that: a) 3 is selected?
\n" ); document.write( "b) 3 or 4 is selected?
\n" ); document.write( "c) 3 is not selected? \n" ); document.write( "

Algebra.Com's Answer #740702 by ikleyn(52943) $\"\"$ $\"About$

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\n" ); document.write( "The names of four students are placed in a small box and two will be selected to represent the
\n" ); document.write( "school in an oratory contest. Let 1, 2, 3 and 4 denote the students. What is the probability that: a) 3 is selected?
\n" ); document.write( "b) 3 or 4 is selected?
\n" ); document.write( "c) 3 is not selected?
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\n" ); document.write( "\n" ); document.write( "a). What is the probability that #3 is selected ?\r
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document.write( "    In all, there are   =  = 6 ways to form the groups of 2 students from 4 students.\r\n" );
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document.write( "    And there are only 3 groups of two students that contain #3 as a member, because you can add one \r\n" );
document.write( "    of the 3 students #1, #2 and/or #4 to the #3 in three ways.\r\n" );
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document.write( "    So, the probability under this question is   = .\r\n" );
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\n" ); document.write( "\n" ); document.write( "b). What is the probability that #3 or #4 is selected ?\r
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document.write( "     If NEITHER  #3  NOR   #4  is selected, then there is only one such a group of two students: it is the group comprising of  #1  and  #2.\r\n" );
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document.write( "     The total number of groups of 2 from 4 is 6, as we calculated it in the solution a).\r\n" );
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document.write( "     So the probability under this question is   = .\r\n" );
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\n" ); document.write( "\n" ); document.write( "c). What is the probability that #3 is not selected? ?\r
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document.write( "     The number of groups of 2 students from 4 that do not contain #3 is   =  = 3.\r\n" );
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document.write( "     The entire number of groups by 2 from 4 is 6, as we calculated it in the solution a).\r\n" );
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document.write( "     So the probability under this question is   = .\r\n" );
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