Answer

A base 10 analogy will be helpful.
In base 10 we start with 10^0, 10^1 etc for the “values of the position” to the “left” of the decimal point. For the “values of the positions” to the “right” of the decimal point, its 10^(-1), 10^(-2) etc.

Hexadecimal is just base 16.
Similarly, In base 16 we start with 16^0, 16^1 etc for the “values of the position” to the “left” of the decimal point. For the “values of the positions” to the “right” of the decimal point, its 16^(-1), 16^(-2) etc.

So for 16.3852 we get
For the “left of the decimal”, value of ‘6’ is just 6 multiply the “value of this position” which is “16^0″… and so on. We get,
16. 3852
=1*16^1+ 6*16^0+ 3*16^(-1)+ 8*16^(-2)+ 5*16^(-3)+2*16^(-4)
= 22.22 with a calculator.

With the idea above, one can convert between any base to base 10.