data sufficiency - rajs monthly salary is rs 4000 what is aruns monthly salary i arun gets rs 500 more than the average salary of his and rajs ii average of rajs and aruns salary is rs4500 - skillgun

Please read the below given text for solving the question Each question given below has a problem and two statements numbered I and II giving certain information. You have to decide if the information given in the statements is sufficient for answering the problem. Indicate your answer as (a) if the data in the statement I alone is sufficient to answer the question; (b) if the data in the statement II alone is sufficient to answer the question; (c) if the data either in I or II alone are sufficient to answer to question; (d) if the data even in both the statements together are not sufficient to answer the question; (e) if the data in both the statement together are needed.

From I we have: A-4000=1000 or A=5000. i.e. Arun's monthly salary is 5000.
From II we have A+R/2=4500 or A+4000 = 9000 or A = 5000.
Thus either I or II is sufficient.