Question

what will happen if salt is added to ice?

Answer 1

Salt decreases the melting point of ice as salt being an non volatile solute (anything which doesn't convert into its vapour form), facilitates a depression in freezing point of ice.

Therefore ice will take a longer time to melt.
OR
When you add salt to an ice cube, you end up with an ice cube whose temperature is above its melting point. This ice cube will do what any ice cube above its melting point will do: it will melt. As it melts, it cools down, since energy is being used to break bonds in the solid state.