CAT (QA) PYQs

Anil can paint a house in $60$ days while Bimal can paint it in $84$ days. Anil starts painting and after $10$ days, Bimal and Charu join him. Together, they complete the painting in $14$ more days. If they are paid a total of Rs. $21000$ for the job, then the share of Charu, in INR, proportionate to the work done by him, is

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?

Humans and robots can both perform a job but at different efficiencies. Fifteen humans and five robots working together take thirty days to finish the job, whereas five humans and fifteen robots working together take sixty days to finish it. How many days will fifteen humans working together (without any robot) take to finish it?