Hi Dr Uma,

I came across a free-response question from the Princeton Review. However, I could not get (c) because they used the value 380 J instead of -380 J. Wouldn't that contradict (b), as to calculate the specific heat of Al we used -380 J. Also, it is the cooling of aluminum so shouldn't it indicate an exothermic process?   

You can express  it as heat lost by Al or heat gained by water.
I think they've given answer in terms of heat gained by water.