A 43.27-g sample of water at 85.7 celcius is added to a sample of water at 24.5 celcius in a constant-pressure?

[Jae de Laon]

A 43.27-g sample of water at 85.7 celcius is added to a sample of water at 24.5 celcius in a constant-pressure calorimeter. If the final temperature of the combined water is 39.9 celcius and the heat capacity of the calorimeter is 26.3 J/celcius, calculate the mass of the water orginally in the calorimeter.
m= ( )g