At the beginning of the summer, swim team A and swim team B each had m members, and no one was a member of both teams. At the end of the summer 6 members left swim team A and 4 members left swim team B. How many members did swim team A have at the beginning of the summer? (1) The ratio of the total number of members who left the two teams at the end of the year to the total number of members at the beginning of the year is 15-->. (2) At the end of the summer 21 members remained on swim team B.

Data Sufficiency questions are exclusive to the GMAT.

Each Data Sufficiency question poses a question, followed by two statements. Your task is to evaluate the statements to determine at what point there is or is not sufficient information to answer the question.

Unlike the Problem Solving questions, you do not actually have to answer the question posed. Instead, you select one of five fixed answer choices that offer different options about the sufficiency of the information provided in the two statements.