2. For a glass of juice, Xiao Ming drank 3/ 1, then filled it with water, drank half of it, filled it with water and drank 4/ 1, and continued to fill it with water. Finally, he drank the diluted juice in one gulp. How much is Xiaoming's juice and water?

3. Divide the 4m-long rope into 7 segments on average, each segment accounts for () of this rope, and each segment is () long.

4. Judges.

If 8/a is a false score and 10/a is a true score, then a must be 9. ( )

When the side length of a cube is tripled, its surface area is multiplied by nine times.