A question is given followed by information in three statements. You have to find out the data in which statement(s) is sufficient to answer the question and mark your answer accordingly.

Average age of 8 sons and two daughters is 15 years. Find the age of elder daughter (in years) is∶

I) Difference between the age of elder daughter and the younger daughter is 6 years.

II) The average age of 8 sons of a family is 12.