Answer :
1 dozen is 12.
So,
12 dozen is 12 x 12 = 144
Now,
Cost of 144 shirts at $8.75 each is:
[tex]\begin{gathered} 144\times8.75 \\ =\$1260 \end{gathered}[/tex]The salesman will receive 12.5% of $1260.
12.5% in decimal is
12.5/100 = 0.125
The commission is:
[tex]\begin{gathered} 0.125\times1260 \\ =\$157.50 \end{gathered}[/tex]