50,000 / 2500 = 20....he bought them for 20 bucks a piece. So if he wants to sell them at 15% profit, he would sell them for 20 + 0.15(20) = $ 23 bucks.
A 15% profit of 50,000 dollars is 0.15(50,000) = 7500. Plus the 50 grand spent totals 57500. So they want to make a $ 7500 profit. Selling 2500 lamps at $ 23 per lamp (2500 x 23 = 57500) makes them their profit.
I should just shut up now...answer is $ 23 per lamp
