The mass of density bottle is 20g when empty,70g when full of water and 55g when full of a second liquid. Calculate the density of the liquid?

Answer 1

you have 50g of water
so the 2nd liquid has density 55/50 * (density of water)

Answer 2

oops. you only have 35g of the 2nd liquid (20g of glass)
So its density is 35/50 that of water.