A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Explanation: Given: \((X+Y)/2 = 20 \Rightarrow X+Y = 40\). We need to find the average of X, Y, and Z, which is \((X+Y+Z)/3 = (40+Z)/3\). To find the average, we need a specific value for Z. Statement 1: \(5 < Z < 8\). Z can be any real number (e.g., 6, 7, 6.5) in this range. Not sufficient. Statement 2: \(3 > Z > X\). This is an inequality. Z can be many values, e.g., if \(X=1\), \(Z\) could be \(2\). If \(X=10\), \(Z\) could be \(1\). Not sufficient. Together: From (2), \(X < 3\). From (1), \(5 < Z < 8\). There is no conflict between \(X\) and \(Z\) values, but Z still has a range of possible values, so \(Z\) is not specific. Therefore, the value of \((40+Z)/3\) is not specific. NOT sufficient.