A question is given, followed by two statements labelled I and II. Identify which of the statements is/are sufficient/necessary to answer the question. Question: Arvind has blue, green and white marbles. What is the percentage of white marbles out of all the marbles he has? Statements: (I) The sum of blue and green marbles he has is 7. (II) He has 3 white marbles out of 10 marbles.