Novak Design Works generated $$387,200$ in operating income on sales revenue of $$2,420,000.$ The company had

$$1,500,000$ in assets on January $1$ and $$2,900,000$ in assets on December $31.$

$(a-b)$

$($c$)$

Calculate Novak's return on investment. $($Round answer to $2$ decimal places, e$.$g$.5\mathrm{.}12\%.)$