CAT (QA) PYQs

A tank is emptied everyday at a fixed time point. Immediately thereafter, either pump $A$ or pump $B$ or both start working until the tank is full. On Monday, $A$ alone completed filling the tank at $8 \mathrm{pm}$. On Tuesday, B alone completed filling the tank at $6 \mathrm{pm}$. On Wednesday, $A$ alone worked till $5 \mathrm{pm}$, and then B worked alone from $5 \mathrm{pm}$ to $7 \mathrm{pm}$, to fill the tank. At what time was the tank filled on Thursday if both pumps were used simultaneously all along?

At their usual efficiency levels, $A$ and $B$ together finish a task in $12$ days. If $A$ had worked half as efficiently as she usually does, and $B$ had worked thrice as efficiently as he usually does, the task would have been completed in $9$ days. How many days would $A$ take to finish the task if she works alone at her usual efficiency?

Amal can complete a job in $10$ days and Bimal can complete it in $8$ days. Amal, Bimal and Kamal together complete the job in $4$ days and are paid a total amount of Rs $1000$ as remuneration. If this amount is shared by them in proportion to their work, then Kamal's share, in rupees, is