Coding and Decoding Questions

If 3*1 = 20, 6*1 = 50 and 2*6 = -40, then find the value of 5*8 = ?

In a certain code language, "COPIOUS" is written as "2345389" and "GENEROUS" is written as "16760389". How is "PIGEON" written in that code language?

In a certain code language, "OPTIMIST" is written as "LKRNRGHG". How is "PESSIMIST" written in that code language?

In these questions, the relationship between two elements is shown in the statements. These statements are followed by two conclusions.
Statement:
Y > A < N, Y = B <P
Conclusion:
I. P > A
II. N > B

If RESEARCH is $#!#%$&@ then SCARE is

If SYSTEM is written as RXRSDL.
How can CORRECT be written in that code?

In a code language, if LUCK is written as L2U1C3K1, then what is the last digit for the code for XEROX in that same language?

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
c_e_cd_f_d_f