Given :
Mass of gasoline , m = 50 kg .
Length of tank , l = 0.9 m.
Breadth of tank , b = 0.5 m .
Relative density of gasoline , R.D = 0.75 .
Density of water ,
.
To Find :
The depth of tank .
Solution :
We know ,

Now , volume of gasoline is :

Since , the tank is rectangular , volume is given by :

Therefore , the answer in centimetres is 14.8 cm .
Hence , this is the required solution .