CAT (QA) PYQs

Mayank buys some candies for Rs $15$ a dozen and an equal number of different candies for Rs $12$ a dozen. He sells all for Rs $16.50$ a dozen and makes a profit of Rs $150$. How many dozens of candies did he buy altogether?

One part of a hostel's monthly expenses is fixed, and the other part is proportional to the number of its boarders. The hostel collects $1600$ per month from each boarder. When the number of boarders is $50$, the profit of the hostel is $200$ per boarder, and when the number of boarders is $75$, the profit of the hostel is $250$ per boarder. When the number of boarders is $80$, the total profit of the hostel, in INR, will be

A shopkeeper sells two tables, each procured at cost price $p$, to Amal and Asim at a profit of $20\%$ and at a loss of $20\%$, respectively. Amal sells his table to Bimal at a profit of $30\%$, while Asim sells his table to Barun at a loss of $30\%$. If the amounts paid by Bimal and Barun are $x$ and $y$, respectively, then $(x -y) / p$ equals