$\text{A.}$ $2 x < 3 y < 5 z$ $\text{B.}$ $5 z < 2 x < 3 y$ $\text{C.}$ $3 y < 5 z < 2 x$ $\text{D.}$ $3 y < 2 x < 5 z$
【答案】 D

【解析】 $\left(2^x\right)^{30}=\left(3^y\right)^{30}=\left(5^z\right)^{30} \cdot \Rightarrow\left(2^{15}\right)^{2 x}=\left(3^{10}\right)^{3 y}=\left(5^6\right)^{5 z}$.
\begin{aligned} & \left(2^x\right)^{30}=\left(3^y\right)^{30}=\left(5^z\right)^{30} . \Rightarrow\left(2^{15}\right)^{2 x}=\left(3^{10}\right)^{3 y}=\left(5^6\right)^{5 z} . \\ & \because 25 < 32,8 < 9 . \quad \therefore 5^6 < 2^{15} < 3^{10} . \quad \therefore 2 x < 3 y < 5 . \end{aligned}