<PRE><B>Question 354249</B>
Hi,

*Note:  The number of combinations of a set of n objects taken r at a time is given by nCr = (n!)/(r!(n - r)!).   
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How many committees can be formed from a group of 9 doctors if each committee consists of 7 doctors
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9 choose 7
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{{{9C7 = (9!/(7!*2!))= (9*8*7*6*5*4*3*2*1)/(7*6*5*4*3*2*1*(2*1)))=}}}
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Leaving:
{{{9C7 =(9*8)/2}}} = 36 ways</PRE>