Indicate the formula for the following conditions.

C (n, r)

The formula for C (n, r), also known as "n choose r" or a combination,

is:

nCr = n! / (r! (n-r) !),

where n is the total number of options and r is number you must choose

The number generated is the total number of possible combinations.

The! means factorial. For example, 4! = 4 x 3 x 2 x 1