Answer:
weight of chalk = 25g
Explanation:
let chalk contains 10x calcium, 3x carbon, 12x oxygen.
percentage of carbon in the chalk:
= 3x x 100
10x + 3x + 12x
= 3x ( 100 )
25x
= 3 (4)
= 12%
Now, we know that carbon has 12% of chalk.
weight of carbon = 12% x weight of chalk. ------------- equation
plugin values into the equation:
3 = 12% (weight of chalk)
3 = 12 (weight of chalk)
100
12 (weight of chalk) = 3
100
weight of chalk = 3 (100)
12
weight of chalk = 25g