Two members of a certain club are selected to speak at the next club meeting. If there are 78 different possible selections of the 2 club members, how many members does the club have?	Choose the correct choice from the following options
A) 5	B) 6	C) 7	D) 8	E) 13
Method-1   Total No. of Selection of r out of n objects are defined by nCr = n! / [(r!)(n-r)!]   i.e. If total member = n   then nC2 = n! / [(2!)(n-2)!] = 78   i.e. n*(n-1)*n-2!/ [(2!)n-2!] = 78   i.e. n*(n-1) = 156   (for Positive Values of n)   therefore, n*(n-1) = 156   i.e. n= 13   Answer: Option 13
<result>E</result>
Two members of a certain club are selected to speak at the next club meeting. If there are 78 different possible selections of the 2 club members, how many members does the club have?