I need to find the calorimeter constant for this experiment.

Question

Mass of nested cups (two cups inside one another): 3.04 g
Mass of single cups: 1.51 g
75 mL of cold water goes into nested cup: 76.045 g and the temp. remained constant at 23.0
75 ml of warm water into single cup: 72.755 g and the temp. dropped from 64.75 to 61.25
75 mL of warm water and 75 mL of cold water are placed into the nested cups and a cup is placed overtop of the nested cups to create the calorimeter. The change in temp. for the hot and cold water mixed was 38.5 to 40.75