Let the mass of water = m kg
Specific heat capacity of water = 4200J/°C-kg
Energy absorbed by water = 4032KJ = 4032000J
Change in temperature ( delta T) = 58-50 = 8°C
Q=mc( delta T)
Q = heat energy
m = mass
c = specific heat capacity
Delta T = change in temperature
4032000 = m×4200×8
m = 4032000/(4200×8)
m = 120kg