(i) Chalk contains calcium, carbon and oxygen in the ratio 10:3:12. Find the percentage of carbon in chalk.
(ii) If in a stick of chalk, carbon is 3g, what is the weight of the chalk stick?
(i) Ratio of calcium, carbon, and oxygen = 10: 3: 12
As 10 + 3 +12 = 25,
Therefore, percentage of carbon = = 12%
(ii) Let the weight of the stick be x g.
12 % of x = 3