A $40\ \text{g}$ ice cube at $0\ ^\circ\text{C}$ is put into $0.25\ \text{kg}$ of juice (treat it as water) at $30\ ^\circ\text{C}$. What is the final temperature once the ice has melted? (Latent heat of fusion $3.34 \times 10^{5}\ \text{J/kg}$, $c = 4186\ \text{J kg}^{-1}\text{K}^{-1}$.)