Assume the CAPM holds. There are $3$ investors, A$,$ B$,$ and C$,$ and $3$ stocks, $x,Y,$ and $Z.$

You observe that

A: holds $$4000$ of stock $x$ and $$2000$ of stock $Y$;

B: holds $$1000$ of stock $Y$ and $$3000$ of stock $Z.$

C: holds $$4000$ of stock $x.$

But you do not oberve A$\text{'}$s holding of Z$,$ B$\text{'}$s holding of $x,$ and C$\text{'}$s holding of $Y$ and $Z.$

Based on your observations, you can conclude $C$ holds $

of stock $Z($keep $2$ decimal places$).$