why is sugar soluble in both water and petrol?

Sugar dissolves in water because energy is given off when the slightly polar sucrose molecules form intermolecular bonds with the polar water molecules. The weak bonds that form between the solute and the solvent compensate for the energy needed to disrupt the structure of both the pure solute and the solvent.
Sugar dissolve in water but do not dissolve to any great extent in most organic solvents.