Salt would dissolve better in hot water because, when substances have a high temperature, they have more energy. The more energy molecules have, the faster they move. The molecules in hot water move faster than cold water because of the higher energy. Because the molecules of hot water move fast, they can more easily break apart the other molecules of a different substance when they come into contact.
Salt dissolves faster in hot water because energy molecules are moving fast in the water because of the high temperature in the water.
It is true that the hotter the temperature the more soluble a solute is, but for salt (NaCl) the temperature has very little effect of the solubility. At 0 degrees Celsius 34g NaCl can be dissolved in 100g H20, as you increase the temperature the amount dissolved changes with a slope of .06. In other words at 100 degrees Celsius you can dissolve 40g NaCl in 100g H20. Why this is I have no idea.
I think hot water because I tested this and it works on both
Lol you got that off wiki answers