Chalk contains 10% calcium, 3% carbon and 12% oxygen. Find the amount of carbon and calcium (in grams) in 2 1/2 kg of chalk.
Carbon = 75 g, Calcium = 250 g
Total weight = 2500 g. Carbon = 3% × 2500 = 75 g. Calcium = 10% × 2500 = 250 g.