Question

An empty bottle weighs 20g and 60g when filled completely with water.What will it weigh when filled completely with mercury?


20÷60=0.3

Answer 1

holds 40 g water
that is volume = 40 cm^3
since density of water is about 1 g/cm^3

mass = 20 + 40*density of Hg

density of Hg = 13.5 g/cm^3
so
mass = 20 + 40*13.5 grams

Answer 2

by the way, what we worked with here was mass, not weight.
If this is a Physics course, your book should do mass in kg and weight in Newtons or mass in g and weight in dynes.
weight = mass * acceleration of gravity.
mass is the same on another planet, weight is different.

Answer 3

V=20/69=0.3