Two positive quantities,$\displaystyle p$ and $\displaystyle q$,very in such a way that $\displaystyle {p^3}{q}=9$.Another quantity $\displaystyle z$,is defined by $\displaystyle z=16p+3q$.Find the values of $\displaystyle p$ and $\displaystyle q$ that makes $\displaystyle z$ a minimum.

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