The water temperature rises from 25C to 28.4C, thats 3.4C so the heat absorbed is
mass x change in temp x shc
= 0.150 x 3.4 x 4186
=2134.86J
Now the bolt release the same energy
So mass x change in temp x shc = 2134.86J
0.085 x (85-28.4) x shc
So
shc = 2134.86 / (0.085 56.6)
= 443 J/KgC