Answer and Explanation:
It is not necessary to know the amount of salt in the aqua, because we know that the presence of salt in the water will increase its density.
In this case, salt increases the mass of the water, without increasing the volume of water. as the egg will not change in volume or water, we know that the density of the egg will be constant, while the change in the mass of the water with the addition of salt, will change the density of the water which will increase progressively until it becomes denser than the egg and, consequently, it will not let the egg sink.
