You need to think through what the problem is telling you. Remember, you have three heats:
qcalorimeter
qwater
qmetal
Each one of these q’s is determined by the equation
q = (m) x (c) x (deltaT)
When you are given the mass of the calorimeter, that’s
the “m” in the equation for qcalorimeter. When you are
given the mass of the water, that’s the “m” in the equation for
qwater. When you are given the mass of the metal, that’s
the “m” in the equation for qmetal.
Also, as explained in the book, the temperatures of the water
and calorimeter are the same throughout the experiment.
Thus, the final temperature of the water minus the initial
temperature of the water is the deltaT in the equations for
both qcalorimeter and qwater. In addition, as explained in
the book, the final temperature of the metal is also the same
as the final temperature of the water and calorimeter. Thus,
the initial temperature of the metal minus the final
temperature of the water is the deltaT in the equation for
qmetal.
There will always be two q’s for which you have enough
information to get numbers. There will be one q where you
are missing information, but you can figure that out using
the calorimetry equation:
-qmetal = qwater + qcalorimeter
Solving for the q you do not know will then allow you to use
that q’s equation to solve for the unknown in the problem.