The density of that object is 5.8 gm/cm³.
We know that every 5.8 gm of it we have takes up 1 cm³.
We have to find out how many 5.8 gm we have.
(136.5 g) / (5.8 gm) = 23.53 of them.
Each 5.8 gm fills 1 cm³ of space.
So the 23.53 of them that we have fill 23.53 cm³ of space.
That's the volume of our object.