The price at which the cameras are bought is $1800 for a dozen. This gives the price of each camera as 1800/12 = $150

He sells them at a profit of $36 per camera. The selling price is $150 + $36 = $186.

The profit as a percentage of the selling price is (36/186)*100 = 19.35%

**The required profit as a percentage of the selling price is 19.35%**