Answer:
10
Step-by-step explanation:
Specific gravity (also called relative density) is the ratio of the density of an object (or substance) to the density of a reference substance (mostly water). It has no unit and is given by the following;
Specific gravity =
Specific gravity is also given by the ratio of the weight of the object in air to the loss of weight of the object in water. i.e
Specific gravity =
--------------(* * *)
In this case;
i. The object is the solid which has a weight of 20gf in air.
ii. The loss of weight of the solid in water is the difference between the weight in air (20gf) and the weight in water (18gf).
Therefore the loss of weight is
20gf - 18gf = 2gf
Now substitute these values from (i) and (ii) into equation (* * *) as follows;
Specific gravity =
Specific gravity = 10
Therefore the specific gravity of the solid is 10