Theorem 9.5.1: The number of subsets of size r that can be chosen from a set of n elements is denoted as P(n,r) and is given by the formula:
P(n,r) = n! / (r!(n-r)!)
where n and r are nonnegative integers with r ≤ n.
The notation P(n,r) is also called an r-combination.
Compute each of the following using the given theorem.
a)
b)
c)
d)
e)
f)
b