To calculate the mass percent of an element in a compound, we divide the mass of the element in 1 mole of the compound by the compound's molar mass and multiply the result by 100.

The combustion reaction is $\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\stackrel{}{\to }{\mathrm{CO}}_2\left(\mathrm{g}\right)$

$\mathrm{C}\%=\frac{12}{44}\times \frac{\text{ Wt. of }{\mathrm{CO}}_2}{\text{ Wt. of organic compound }}\times 100$

$60=\frac{12}{44}\times \frac{\text{ Wt. of }{\mathrm{CO}}_2}{0.5}\times 100$

Wt. of ${\mathrm{CO}}_2=1.1$