Question: If there are 2 number system, e.g. Decimal Number System with 10 symbols (0-9) and hexadecimal with 16 Symbols (0-9,A-F), can i conclude that with hexadecimal, i will be able to retain greater accuracy than with the decimal number system due to the higher number of symbols ??

Edit1:
Sorry, i was asking only from the point of view of a computer, it may be for a written calculation or anything

Answer: 
Accuracy is related to non-integer (real) numbers. It depends on 

1. Radix (decimal, hex)
2. Amount of digits

For same amount of digits hex can be more accurate.

Simplest example: Radix: decimal and binary. Amount of digits: 1.

In case of decimal you can have from `0.0` to `0.9`, in case of binary only `0.0` to `0.1` (`0.5` in dec). Decimal is 5 times more accurate.
No, 0x0f = 15(base 10). Neither has greater accuracy, one just has more characters. And remember these representations are for our benefit, your computer sees everything as binary.