document.write( "Question 1205549: A club consists of 16 men and 17 women. In how many ways can they choose a president, vice president, treasurer, and secretary, along with an advisory committee of six people? \n" ); document.write( "
Algebra.Com's Answer #842431 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "16 men + 17 women = 33 people total\r
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\n" ); document.write( "\n" ); document.write( "33*32*31*30 = 982080 ways to pick the president, VP, treasurer and secretary. Order matters because the seats or positions have different names.
\n" ); document.write( "The basic idea is to start at 33 and count down by 1 until 4 slots are accounted for. We multiply each value along the way.
\n" ); document.write( "Alternatively, you can use the nPr formula with n = 33 and r = 4.\r
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\n" ); document.write( "\n" ); document.write( "After 4 people are chosen for those named seats there are 33-4 = 29 people left and there are 6 committee seats to fill.
\n" ); document.write( "Unlike the previous 4 positions, order will not matter with these new 6 seats.
\n" ); document.write( "This is because each person on the 6-person committee is of equal rank.
\n" ); document.write( "Note how none of the 6 seats are named. \r
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\n" ); document.write( "\n" ); document.write( "We have n = 29 people and r = 6 seats to fill.
\n" ); document.write( "Using the nCr combination formula we get:
\n" ); document.write( "n C r = (n!)/(r!(n-r)!)
\n" ); document.write( "29 C 6 = (29!)/(6!*(29-6)!)
\n" ); document.write( "29 C 6 = (29!)/(6!*23!)
\n" ); document.write( "29 C 6 = (29*28*27*26*25*24*23!)/(6!*23!)
\n" ); document.write( "29 C 6 = (29*28*27*26*25*24)/(6!)
\n" ); document.write( "29 C 6 = (29*28*27*26*25*24)/(6*5*4*3*2*1)
\n" ); document.write( "29 C 6 = 342014400/720
\n" ); document.write( "29 C 6 = 475020\r
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\n" ); document.write( "\n" ); document.write( "Pay close attention to the fact \"29*28*27*26*25*24\" is in the numerator of that nCr calculation above. The \"29*28*27*26*25*24\" calculates the permutation npr(29,6). We divide by 6! = 6*5*4*3*2*1 = 720 because this is the number of ways to rearrange any group of 6 people.\r
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\n" ); document.write( "\n" ); document.write( "We found that...
  • 982080 ways to pick president, VP, treasurer and secretary (order matters)
  • 475020 ways to pick the 6-person committee (order doesn't matter)
There will be 982080*475020 = 466,507,641,600 (roughly 466.5 billion) different ways to select all 10 people.\r
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\n" ); document.write( "\n" ); document.write( "Effectively we just computed: npr(33,4)*ncr(29,6)\r
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\n" ); document.write( "\n" ); document.write( "Alternatively you can compute it like this: ncr(33,6)*npr(27,4)
\n" ); document.write( "Why does this work? Because we can form the committee of 6 people first, and then we'd have 33-6 = 27 people left to pick from to select the president, VP, treasurer, and secretary. \r
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\n" ); document.write( "\n" ); document.write( "Answer: 466,507,641,600
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