Question

If Chalk contains Calcium, Carbon, and Oxygen in the ratio $10:3:12$.If in a stick of chalk, carbon is $3g$, what is the weight of the chalk stick?

Answer 1

Given: Weight Ratio, Calcium:Carbon: Oxygen $=10:3:12$

So, Weight of calcium in chalk stick $=10x$

Weight of Carbon in chalk stick $=3x$

and, Weight of oxygen in chalk stick $=12x$

It is given that the weight of carbon in this chalk is $3g$

$\therefore 3x=3$

$\Rightarrow x=1$

Weight of the chalk stick $=10x+3x+12x$

$=(10\times 1)+(3\times 1)+(12\times 1)$

$=10+3+12=25g$

Hence, the weight of the chalk stick will be $25g$ when the carbon is $3g$.