5 moles of A and 6 moles of Z are mixed with sufficient amount of C to produce the final product F. Find out the maximum moles of F which can be produced .Assume that the product formed can also be reused .Reactions are
$A+2Z\stackrel{ }{\to }B$ 
$B+C\stackrel{ }{\to }Z+F$

Because the product(z) can also be reused as a reactant so Z will not be a limiting reagent. Here ‘A’ will be limiting reagent 
 $\begin{array}{l}A+2Z\stackrel{ }{\to }B\\ 5 0\\ 0 5\\ B+C\stackrel{ }{\to }Z+F\\ 5 0 0\\ 055\end{array}$