a piece of solid weighs 120g in air, 80g in water and 60g in a liquid, then the relative density of the solid and taht of solid and that of liquid are what ?

The relative density of an object is equal to the ratio of its weight in air and the difference of its weight in air and its weight when the object is submerged in water.
D = [(Wa)/(Wa−Ww )]
From the given data D = [120/(120−80)]
⇒D = (120/40)
⇒D =3.
Relative density of oil can be calculated as,
⇒Relative density of oil = Loss in weigh in oil/ Loss in weigh in water
⇒Relative density of oil = (120 – 60 )/(120 − 80)
⇒Relative density of oil = 60/40
⇒Relative density of oil = 1.5