CAT (QA) PYQs

The average number of copies of a book sold per day by a shopkeeper is 60 in the initial seven days and 63 in the initial eight days, after the book launch. On the ninth day, she sells 11 copies less than the eighth day, and the average number of copies sold per day from second day to ninth day becomes 66. The number of copies sold on the first day of the book launch 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

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