M = mass of aluminium = 1.11 kg
[tex] c_{a} [/tex] = specific heat of aluminium = 900
[tex] T_{ai} [/tex] = initial temperature of aluminium = 78.3 c
m = mass of water = 0.210 kg
[tex] c_{w} [/tex] = specific heat of water = 4186
[tex] T_{wi} [/tex] = initial temperature of water = 15 c
T = final equilibrium temperature = ?
using conservation of heat
Heat lost by aluminium = heat gained by water
M [tex] c_{a} [/tex] ([tex] T_{ai} [/tex] - T) = m [tex] c_{w} [/tex] (T - [tex] T_{wi} [/tex] )
(1.11) (900) (78.3 - T) = (0.210) (4186) (T - 15)
T = 48.7 c