Bought n mangoes. Sold 0.9n mangoes. Since the total profit was Php 50.00, it means that the vendor sold 0.9n mangoes for 175 + 50 = 225 pesos. The equation to find "n" is 0.9*n*2.50 = 225 pesos. From the equation, n == 100. ANSWER. He purchased 100 mangoes.