Answer:
Check body of the explanation
Explanation:
Ooook, quick theory rushdown. if you're at a depth of h in a tank of a fluid, the pressure is the sum of the atmosferic pressure (if the tank is open on top) plus a term which is the product of acceleration of gravity - about 
, the density of whatever you're sinking in, and the depth at which you are. In formula, 
, and the pressure is the same for every point of the tank at the same depth.
At this point, we can start answering!
1a. The pressure at A is - not counting atmosferic pressure - 
, while in B is 
, so it's half of it.
1b. The two points are at the same depth, so the pressure is the same - they would be even if the two cilinders weren't linked!
1c. Ditto. Same depth? same pressure!
1d. Usual equation, this time density is 800. Pressure is 
: Since the density is 4/5 of water, the pressure is also 4/5 of the one exerted by water
2a. The volume is simply the product, so 
2b. Density is defined as mass over volume, so you simply multiply the volume you found earlier by the density of paraffine: 
2c. Weight is defined as the mass of something times the acceleration due to gravity, in our case it's 
2d. 
again, what a surprise! 
3. Yet again, . 
