This answer gives the correct total number of items sold, but not the correct total revenue. Twenty-three T-shirts sell for $\displaystyle{23}\cdot{12}={276}\usepackage{cmbright}\Huge\$ dollars, while 16 pairs of shorts sell for $\displaystyle{16}\cdot{9}={144}\usepackage{cmbright}\Huge\$ dollars. This would be a total of $420, not $414. The correct equations with which to start the problem are:

(A) $\displaystyle{t}+{s}={39}\usepackage{cmbright}\Huge\$

(B) $\displaystyle{12}{t}+{9}{s}={414}\usepackage{cmbright}\Huge\$