Let x be the number of t-shirts and y the number of shorts they sold. Since in total they sold 266 items we have the equation:
[tex]x+y=266[/tex]Now we know that each shirt cost $2 and each short cost $4 and that the total sales were $672 then we have the equation:
[tex]2x+4y=672[/tex]Hence we have the system of equations:
[tex]\begin{gathered} x+y=266 \\ 2x+4y=672 \end{gathered}[/tex]Solving for y from the first equation we have:
[tex]y=266-x[/tex]Plugging this in to the second equation we have:
[tex]\begin{gathered} 2x+4(266-x)=672 \\ 2x+1064-4x=672 \\ -2x=672-1064 \\ -2x=-392 \\ x=\frac{-392}{-2} \\ x=196 \end{gathered}[/tex]Plugging this value in the equation for y we have:
[tex]y=266-196=70[/tex]Therefore the sold 196 shirts and 70 shorts.