IIM-B (BBA-DBE) 2024 #2 (QA) PYQs

Work done by P in one day is double the work done by Q in one day and work done by Q in one day is thrice the work done by R in one day. If P, Q, and R together can complete the work in 30 days, then in how many days P alone can do the work?

Two pipes P and Q can fill a tank in $20$ hrs and $25$ hrs respectively while a third pipe R can empty the tank in $30$ hrs. If all the pipes are opened together for $10$ hrs and then pipe R is closed, then in what time the tank can be filled?

81 equally efficient people could complete a piece of work in 15 days. Initially 45 such people started working together. But after they worked together for 6 days their employer wanted that the work should be completed in a total of 21 days. However any new worker who joins is only 60% as efficient as any of the 45 people already working. How many new workers did the employer hire to work alongside the initial 45 people to meet the deadline?