CAT (QA) PYQs

Manu earns Rs. $4000$ per month and wants to save an average of Rs. $550$ per month in a year. In the first nine months, his monthly expense was Rs. $3500$, and he foresees that, tenth month onward, his monthly expense will increase to Rs. $3700$. In order to meet his yearly savings target, his monthly earnings, in rupees, from the tenth month onward should be

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

A class consists of $20$ boys and $30$ girls. In the mid-semester examination, the average score of the girls was $5$ higher than that of the boys. In the final exam, however, the average score of the girls dropped by $3$ while the average score of the entire class increased by $2$. The increase in the average score of the boys is