Four cubes of ice at $-{10}^0\mathrm{C} \mathrm{each} \mathrm{one} \mathrm{gm} \mathrm{is} \mathrm{taken} \mathrm{out} \mathrm{from} \mathrm{the} \mathrm{refrigerator} \mathrm{and} \mathrm{are} \mathrm{put} \mathrm{in} 150 \mathrm{gm} \mathrm{of} \mathrm{water} \mathrm{at} {20}^0\mathrm{C}.$ The temperature of water when thermal equilibrium is attained. Assume that no heat is lost to the outside and water equivalent of container is 46 gm. (Specific heat capacity of water = 1 cal/gm-${ }^0\mathrm{C}, \mathrm{Specific} \mathrm{heat} \mathrm{capacity} \mathrm{of} \mathrm{ice} = 0.5 \mathrm{cal}/{\mathrm{gm}}^0\mathrm{C}, \mathrm{Latent} \mathrm{heat} \mathrm{of} \mathrm{fusion} \mathrm{of} \mathrm{cie} = 80 \mathrm{cal}/\mathrm{gm}{-}^0\mathrm{C}$