WBJEE 2018 Physics Solved Paper

The water equivalent of a calorimeter is 10 g and it contains 50 g of water at 15°C. Some amount of ice,initially at –10°C is dropped in it and half of the ice melts till equilibrium is reached. What was the initialamount of ice that was dropped (when specific heat of ice = 0.5 calgm–1°C–1, specific heat ofwater = 1.0 calgm–1°C–1 and latent heat of melting of ice = 80 calgm–1) ?