There is a missing part in the question. Found the complete text on internet: "What is the largest size vehicle (kg) it can lift if the diameter of the output line is 28.0 cm? "
Solution The diameter of the piston is 28.0 cm, this means its radius is 14.0 cm (half the diameter), so the area of the piston is [tex]A=\pi r^2 = \pi (0.14 m)^2 =6.15 \cdot 10^{-2} m^2[/tex] The maximum pressure of the lift is [tex]p=18.0 atm = 1.82 \cdot 10^6 Pa[/tex] Therefore the maximum force the piston can lift is [tex]F=pA=(1.82 \cdot 10^6 Pa)(6.15 \cdot 10^{-2} m^2)=1.12 \cdot 10^5 N[/tex] And the size (the mass) of the vehicle is [tex]m= \frac{F}{g}= \frac{1.12 \cdot 10^5 Pa}{9.81 m/s^2} =1.14 \cdot 10^4 kg [/tex]
