we'll proceed along the same lines as the previous one.
the cost of the boots is 90.10 and that includes 6.25% sales tax, so if "x" is the 100%, then 90.10 is really the 106.25%, because is including the extra 6.25%.
[tex]\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 90.10&106.25\\ x&100 \end{array}\implies \cfrac{90.10}{x}=\cfrac{106.25}{100} \\\\\\ 9010=106.25x\implies \cfrac{9010}{106.25}=x\implies 88.8=x[/tex]
so if that's the cost of each boot, without tax, then the markup will be 88.8 - 50.88 = 37.92.
if the 100% is 88.8, how much is 37.92 off of it in percentage?
[tex]\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 88.8&100\\ 37.92&x \end{array}\implies \cfrac{88.8}{37.92}=\cfrac{100}{x} \\\\\\ 88.8x=3792\implies x=\cfrac{3792}{88.8}\implies \stackrel{\%}{42.7}\approx x[/tex]
