Total mass of mouthwash = volume*density
1 pint is 568.261 mL therefore 1.040 pints = 591.0 mL (4 significant figures)
Therefore mouthwash mass in a bottle = 591.0 mL * 0.851 g/mL = 503 g (3 s.f.)
In 160 bottles, ethanol mass = 509 g * 160 * 0.381 = 30700 g = 30.7 kg
