This is a common laboratory experiment called calorimetry which determines the specific heat capacity of the sample metal.
By the Conservation of Energy,
Energy of Metal = Energy of Water
mCmetalΔT = mCwaterΔT, wherein Cwater = 4.187 J/g·°C
(26.5 g)(Cmetal)(98 - 32.5°C) = (150 g)(4.187 J/g·°C)(32.5 - 20°C)
Solving for Cmetal,
Cmetal = 4.523 J/g·°C