how many gram HCl is needed to react completely with 200g of 40%pure marble chips?

Chemical reaction between HCl and CaCO₃​ : 

CaCO₃ + 2HCl $\to$CaCl₂ + CO₂ + H₂O 

$$\begin{gathered} 2 mol of HCl (2\times 36.5 =71gm) react with 100\% pure 1mol of CaC{O_3}_{}\left(100gm\right) \\ if marble \left(CaC{O}_3\right) is 40\%\hspace{0.17em}pure then 28.4gm of HCl is needed to react. \\ Thus, \\ if 40\% pure 100 gm CaC{O}_3 require 28.4gm of HCl \\ 40\% pure 200 gm CaC{O}_3 require = 200\times 28.4/100 \\ =56.8gm of HCl \end{gathered}$$