Ta có :\(d=\dfrac{P}{V}\) mà \(P=10m\Rightarrow d=\dfrac{10m}{V}\)

và \(D=\dfrac{m}{V}\)

\(\Rightarrow\dfrac{d}{D}=\dfrac{\dfrac{10m}{V}}{\dfrac{m}{V}}=\dfrac{10m}{V}:\dfrac{m}{V}=\dfrac{10m}{V}\cdot\dfrac{V}{m}=10\)

\(\Rightarrow\dfrac{d}{D}=10\)

\(\Rightarrow d=10D\)