Unit operating expenses for an item costing $$25$ are estimated at $40\%$ of cost$,$ and the desired operating profit is $10\%$ of cost$.$a$.$ Determine the selling price. $($Do not round intermediate calculations and round your final answer to $2$ decimal places.$)$b$.$ Determine the rate of markup on cost$.($Do not round intermediate calculations and round your final answer to $1$ decimal place.$)$c$.$ Determine the rate of markup on selling price. $($Do not round intermediate celculations and round your final answer to $1$ decimal place.$)$