The mass of a full bottle of cooking oil is 1.30 kg when half Is empty calculate mass of empty bottle

Mass of bottle + cooking oil = 1.3 kg

Mass of bottle + 1/2 cooking oil = 0.9 kg

Thus half cooking oil = 1.3 - 0.9

= 0.4 kg

Mass of cooking oil in a full bottle = 0.4 * 2

= 0.8 kg

Therefore the mass of the empty bottle

= 1.3 - 0.8

= 0.5 kg