Follow up math/statistics question: what does c mean in 40c15?

trying to translate to excel

Follow up math/statistics question: what does c mean in 40c15?
C means combination.





combination formula:


nCr = n! / [ (n - r)! * r!]





n = number of trials


r = rate





for example:


There are 4 books. How many ways can 2 out of 4 can be chosen?





use the combination formula:


number of trials n = 4


rate r = 2





so 4C2 = 4! / [ (4 - 2)! * 2! ] = 6
Reply:Joezen,


I thought the letter C is average in school subject


also C is celcius
Reply:In general, nCm means possible combinations from a set of n objects, taken m at a time. In particular.





nPm means permutations from a set of n objects taken m at a time.





In combinations, the order of choice does not matter while it does in permutations. (1,2,3) and (2,3,1) are the same combination but they are not the same permutation.





The general solution for nCm is n factorial / (m factorial times (n-m factorial)).





The general solution for nPm is n factorial / (n-m) factorial