Problem 13 of 25sta-013
A sandwich shop offers 3 kinds of bread, 4 fillings and 2 sides. A lunch is one bread, one filling and one side. How many different lunches can be ordered?
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Solution walkthrough1:26
- A lunch is three separate choices. Draw them as a tree, starting with the breads.
- Each bread can take any of the fillings, so every branch splits in : .
- Each of those can take either of the sides, so every branch splits in : .
- This is the counting principle: multiply the number of options for each choice. .
- Traps: adds , stops at , and is .