Answer : The density of the rock is,

Explanation : Given,
Mass of the rock = 15 g
Initial volume = 25 ml
Increased volume = 36.2 ml
First we have to calculate the volume of the rock.
Volume of rock = Increased volume of water - Initial volume of water
Volume of rock = 36.2 ml - 25 ml = 11.2 ml
Now we have to calculate the density of rock.
Formula used :

Now put all the given values in this formula, we get the density of the rock.

Conversion :

Therefore, the density of the rock is,
