Answer:
10 ways
Step-by-step explanation:
The number of ways to select x elements from a group of n elements is calculated as
These ways are called combinations. In this case, we need to select 3 different extras from a group of 5 extras ( tomato, lettuce, bacon, onion, or cheese). So, the number of ways to make an order is
Therefore, the are 10 different ways to order a burger with three different extras.