Use the Fundamental Counting Principle, or draw a tree diagram, to find the number of possible lunch combinations. There are two breads, two meats, three snacks, and two drinks, so $\displaystyle{2}\cdot{2}\cdot{3}\cdot{2}={24}\usepackage{cmbright}\Huge\$ possible combinations. The event space is {(wheat, roast beef, popcorn, water), (wheat, roast beef, popcorn, juice)}. The size of the event space is 2, so $\displaystyle\frac{{2}}{{24}}\usepackage{cmbright}\Huge\$ , or $\displaystyle\frac{{1}}{{12}}\usepackage{cmbright}\Huge\$ , is the probability of the event occurring.