Three coats of white paint.

I wish Hunter was here to give me an idea what it will cost.' As if in answer to his wish, Nimrod entered the office at that moment, and in reply to Rushton's query said that to give the walls and ceiling three coats of paint would cost about three pounds five for time and material.

Between them the two brain workers figured that fifteen pounds would cover the entire cost of the work--painting and decorating.
'Well, I reckon we can charge Sweater forty-five pounds for it,' said Rushton.

'It isn't like an ordinary job, you know.

If he gets a London firm to do it, it'll cost him double that, if not more.' Having arrived at this decision, Rushton rung up Sweater's Emporium on the telephone, and, finding that Mr Sweater was there, he rolled up the designs and set out for that gentleman's office.
The men work with their hands, and the masters work with their brains.
What a dreadful calamity it would be for the world and for mankind if all these brain workers were to go on strike..