Question

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.

Answer 1

We have,

Percentage of calcium in chalk = 10%

Percentage of carbon in chalk = 3%

Percentage of oxygen in chalk = 12%

∵ Weight of chalk = `2 1/2` kg

= `5/2` kg

= 2.5 kg

= 2.5 × 1000 g  ...[∵ 1 kg = 1000 g]

= 2500 gm   

∴ Amount of carbon in chalk = 3% of 2500 g

= `3/100 xx 2500`

= 25 × 3

= 75 g

∴ Amount of carbon in chalk = 10% of 2500 g

= `10/100 xx 2500`

= 10 × 25

= 250 g

Hence, amount of carbon and calcium are 75 g and 250 g, respectively.