Mass of water in the bottle = Mass of bottle with water - Mass of empty bottle

= 75 -30 = 45g.

Under standard conditions, density of water is 1 g/cm^3.

Hence, volume of water in the bottle = volume of empty bottle = 45 g / cm^3.

Mass of liquid x = 65 - 30 = 35 grams

Density = Mass / Volume = 35 / 45 =0.778 g / cm^3

= 75 -30 = 45g.

Under standard conditions, density of water is 1 g/cm^3.

Hence, volume of water in the bottle = volume of empty bottle = 45 g / cm^3.

Mass of liquid x = 65 - 30 = 35 grams

Density = Mass / Volume = 35 / 45 =0.778 g / cm^3