please solve

Q. What percentage of oxygen is present in the compound CaCO₃ 3Ca₃(PO₄)₂?

      (A) 23.3%                           (B) 45.36%                     (C) 41.94 %                      (D) 17.08%

Dear Student 

The atomic mass of Ca = 40 
                                 O  = 16
                                 P  = 30 
                                C  = 12

So, 
      The total mass of the given compound $CaC{O}_3.3C{a}_3(P{O}_4{)}_2$ is 1030 g 
      Now the total number of atoms of oxygen in the given compound is 27 
So the total mass of oxygen in the given compound will be = 27 x 16 = 432


$$\begin{gathered} \% composition of oxygen = \frac{mass of oxygen in compound }{mass of compound }\times 100 \% \\ = \frac{432}{1030 }\times 100 \\ = 41.94 \% \end{gathered}$$

So, the correct option is (C) 

Regards