Use the Fundamental Counting Principle, or draw a tree diagram, to find the number of possible scarf combinations. There are two fabrics, two trimmings, and three lengths, so $\displaystyle{2}\cdot{2}\cdot{3}={12}\usepackage{cmbright}\Huge\$ possible combinations. The event space is {(cotton, beading, long), (cotton, fringe, long), (silk, beading, long), (silk, fringe, long)}. The size of the event space is 4, so $\displaystyle\frac{{4}}{{12}}\usepackage{cmbright}\Huge\$ , or $\displaystyle\frac{{1}}{{3}}\usepackage{cmbright}\Huge\$ , is the probability of the event occurring.