Which expression represents the number of possible combinations of n items taken r at a time?

Step-by-step explanation:

Given :Total items = n

           Items taken at a time = r

To Find: Which expression represents the number of possible combinations of n items taken r at a time?

Solution:

We will use combination over here.

Now Total items = n

         Items taken at a time = r

Thus expression represents the number of possible combinations of n items taken r at a time is