Pressure and Height in Liquids: A Container with Different Diameter Tubes

[jasonlaiyh]

Homework Statement

A container consists of two tubes, tube A which is wider and tube B which is narrower. The diameter of a tube A is four times that of tube B. Some mercury is poured into the container first and then water is added into the thin tube until it reaches a depth of 70 cm.

a) By how much does the mercury in the big tube rise?

b) By how much does the mercury in the thin tube fall?

c) If the water is poured into the wide tube, what is the difference in height of the mercury level between the narrow tube and the wide tube?

Homework Equations

P=hρg
(though I think no calculations are needed)

The Attempt at a Solution

I really have no idea on how to do this, but I'm guessing that the heights are the same since the pressure is the same?
Please help! This is my own revision and not a homework because my physics paper for my o-level is coming next week.

 

[LawrenceC]

Is the situation a U-tube manometer with a diameter change?

 

[jasonlaiyh]

It's as stated a container with diameter change.
What I understand is that the pressure is not affected by shape.
So the heights should be equal, right?
The problem is I don't know how to get the length.