As a tenderer, you are pricing a contract which includes a number of manholes with an average depth of $2\mathrm{.}6$ m$.$ The total cost of materials per manhole is $$2,500$ and you have decided that you need $25\%$ overheads and $30\%$ profit on those materials. You have allowed for two labourers for $5$ hours each and at an hourly charge of $$25\mathrm{.}70$ each plus $20\%$ for overheads and $15\%$ for profit. The hydraulic excavator will cost $$120$ per hour for $3$ hours and that includes profit and overhead. Calculate the unit rate for a manhole.