Question

You want to repaint the outside of your house and get new blinds. At the store you

have 10 options for the house color, and 11 options for the trim color and 5 colors
for the blinds. How many different combinations do you have to choose from?

Answer 1

Answer: 550

Reason:

Use the multiplication principle, or counting principle, to get 10*11*5 = 550 different combos.

Why do we multiply? Consider a scenario where we have 10 options for the house color and 11 options for the trim color. Ignore the blinds for now. We would have a 10 row and 11 column table with 10*11 = 110 different inner cells to represent the house color and trim color combo. This is why we multiply the values. The idea can be extended to more than two factors.