p_{1} = 900 \frac{k g}{m^{3}} \cdot 10 \frac{N}{k g} \cdot 0, 03 m + 1000 \frac{k g}{m^{3}} \cdot 10 \frac{N}{k g} \cdot 0, 03 m = 570 P a

${p_1 = {900}\,\mathrm{\frac{kg}{m^3}}\cdot {10}\,\mathrm{\frac{N}{kg}}\cdot {0,03}\,\mathrm{m} + {1000}\,\mathrm{\frac{kg}{m^3}}\cdot {10}\,\mathrm{\frac{N}{kg}}\cdot {0,03}\,\mathrm{m} = {570}\,\mathrm{Pa}}$

Error