In a hydraulic system, piston1 has a surface area of 100cm^2 and piston 2 has a surface of 900cm^2.piston 1 exerts a pressure of 10 pa on the fluid in the hydraulic lift. what is the fluid pressure on piston 2? a.10pa b.81pa c.100pa d.90pa

The correct answer is a) 10 Pa.
In fact, the pressure exerted on some point of a fluid is transmitted with equal intensity to every point of the fluid (Pascal's law). 
In this case, therefore, the pressure exerted by piston 1 on the fluid (10 Pa) is transmitted through the fluid to piston 2, with same intensity, 10 Pa.