1 kg water of specific heat $1 cal/gm{-}^{0}C$ is kept in a container at ${10}^{0}C$. If  $500$gm of ice at $0^{0}C$ is required to cool down the water from ${10}^{0}C to 0^{0}C$, the water equivalent of container is  (Latent of fusion for ice $= 80 cal/gm$ and specific heat of water is $1 cal/gm{-}^{0}C$)