Let the mass of ice to be added be mi.
Given : Sw=4200 J/kgoC L=336000 J/kg
Mass of water mw=170 g=0.17 kg
Change in temperature of water ΔT=50−5=45oC
Heat energy released by water in lowering its temperature is absorbed by ice to melt.
Using miL=mwSwΔT
∴ mi×336000=0.17×4200×45
⟹ m=0.0956 kg=95.6 g