I just dont understand how to do this physics question?? :[?

[Tiffany]

A cup is made of an experimental material that can hold hot liquids without significantly increasing its own temperature. The 0.75 kg cup has an initial temperature of 37.1 C when it is submerged in 1.20 kg of water with an initial temperature of 19.9 C.
What is the cup's specific heat capacity if the final temperature is 22.1 C? The specific heat of water is 4186 J/kg x C. Answer in units of J/kg x C.

[Sara]

we use mcT=mcT, because we assume energy flows from the cup to the water........
we also assume it has reached equilibrium, that both the substance are equal in temp....
the negaive sign at the beggining of the eqn shows that heat flows out from the cup...
(-)mc(deltaT)=mc(deltaT)
(0.75)(c)(22.1-37.1)=(1.2)(4186)(22.1-19.9)
c=982

[Richard S]

Ms Tiffany -
I think it is a poorly crafted question: Is the cup really .75 kg? - or, was that the mass of its contents? Let me assume that the question is: ... no,... that doesn't work. Well, maybe... YES! It is a heavy cup and we are not worrying about its contents... nope...
Question: If the cup does not increase its temp. when exposed to heat wouldn't its specific heat be "Infinite J/kg/Cº?
I think your teacher gave you an unanswerable question... - but you should probably not go back to school prepared to "share" my opinion openly.....
Richard