You may have thought that because the probability of choosing a white jersey by itself is $\displaystyle\frac{{1}}{{2}}\usepackage{cmbright}\Huge\$ and the probability of choosing a pair of red shorts by itself is $\displaystyle\frac{{1}}{{3}}\usepackage{cmbright}\Huge\$ , you should add these numbers together. Instead, write out a list of every combination of jersey and shorts and count the number of possibilities to find the size of the sample space. The correct answer is $\displaystyle\frac{{1}}{{6}}.\usepackage{cmbright}\Huge\$