Đề bài ko thiếu nhé :v
\(P=370N\Rightarrow V_{thep}=\dfrac{P}{d_{thep}}=\dfrac{370}{78000}\left(m^3\right)\)
\(F_A=P\Leftrightarrow d_{nuoc}.V_{thep}'=P\Rightarrow V_{thep}'=\dfrac{P}{d_{nuoc}}=\dfrac{370}{10000}=\dfrac{37}{1000}\left(m^3\right)\)
\(\Rightarrow\Delta V_{thep}=V_{thep}'-V_{thep}=\dfrac{37}{1000}-\dfrac{37}{7800}=...\left(m^3\right)\)