CAT (QA) PYQs

The mean of all $4-$digit even natural numbers of the form $'aabb',$ where $a > 0,$ is

A CAT aspirant appears for a certain number of tests. His average score increases by $1$ if the first $10$ tests are not considered, and decreases by $1$ if the last $10$ tests are not considered. If his average scores for the first $10$ and the last $10$ tests are $20$ and 30, respectively, then the total number of tests taken by him is

In an examination, the average marks of students in sections $A$ and $B$ are $32$ and $60$, respectively. The number of students in section $A$ is $10$ less than that in section $B$ . If the average marks of all the students across both the sections combined is an integer, then the difference between the maximum and minimum possible number of students in section $A$ is