So, they give the weight before and after. The density of water is 1g/cm^3. In order to find the space in cm^3 you have to see how many grams the water weighs... 593.63-78.23 = 515.4....so there are 515.4cm^3. Now the formula for density is m/v. So you have the volume of the empty flask and the weight of liquid x. You do 1026.57g/515.4cm^3...And there you go: about 1.9914g/cm^3. (I rounded it)
