Problema Solution

A restaurant has 7 pizza toppings to choose from. How many different 2 topping pizzas are possible?

Answer provided by our tutors

We are dealing with 2-combinations of a set with 7 elements:

C(7, 2) = 7!/(2!(7 - 2)!)

C(7, 2) =  7!/(2!5!)

C(7, 2) = 6*7/2

C(7, 2) = 21

21 different 2 topping pizzas are possible.