Why do both 15c7 and 15c8 both equal 6435?
15C7 = 15! / [15 - 7]!. 7! =15! / [15 - 8]! . 8! =6,435
Study Pascal's Triangle. Look it up!.
15C8 = 15!(8!7!)=15C7
nCr = nC(n-r)
