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?

Ramesh and Ganesh can together complete a work in $16$ days. After seven days of working together, Ramesh got sick and his efficiency fell by $30 \%$. As a result, they completed the work in $17$ days instead of $16$ days. If Ganesh had worked alone after Ramesh got sick, in how many days would he have completed the remaining work?

A group of $N$ people worked on a project. They finished $35 \%$ of the project by working $7$ hours a day for $10$ days. Thereafter, $10$ people left the group and the remaining people finished the rest of the project in $14$ days by working $10$ hours a day. Then the value of $N$ is