How many subsets are in a set with 15 members?

Answer 1

if the members are different then total subsets is equal to 15C1 + 15C2 +....15C15

this is the usual notation of combinatorics.

and nCr is equal to fact(n)/{ fact(r) multiply fact(n-r)}

and Fact(m) = m*(m-1)*(m-2)......3*2*1