To find the comission rate we just have to divide the total comission by the total amount of merchandise sold. The comission was $364 and the amount of merchandise sold was $2800.
[tex]\frac{364}{2800}=0.13[/tex]Then, to rewrite a decimal as a percentage, we just need to multiply the number by 100.
[tex]0.13=\frac{0.13\times100}{100}=\frac{13}{100}=13\%[/tex]The comission rate is 13%.