Black pens sold by all the shopkeepers are what percent of the total pens of all three shops?
Total number of pens sold by A = 50% of 400 = 200 Total number of black pens sold by A = 200 – 500 = 150 Total number of pens sold by B = 75% of 600 = 450 Total number of black pens sold by B = 450 – 190 = 260 Total number of pens sold by C = 60% of 800 = 480 Total number of black pens sold by C = 480 – 80 = 400 Black pens sold by all the shopkeepers = 150 + 260 + 400 = 810 Total pens of all three shops = 400 + 600 + 800 = 1800 Required % = (810/1800) × 100 = 45%