$A, B$ and $C$ individually can do a work in $10\, days, 12\, days$ and $15\, days,$ respectively. The number of days required to finish the work by $A, B$ and $C$ working together is? (in $days$)

$A$ and $B$ together can complete a work in $8$ days. $B$ alone can complete that work in $12$ days. $B$ alone worked for $4$ days. After that,how long will $A$ alone take to complete the remaining work?

$P$ is twice as good a workman as $Q,$ and together they finish a work in $16$ days. In how many days can it be done by each separately?

$A$ can do a certain work in the same time in which $B$ and $C$ together can do it. If $A$ and $B$ together could do it in $10 \text{ days}$ and $C$ alone in $50 \text{ days}$,then $B$ alone could do it in (in $\text{days}$):

$A$ and $B$ together can do a piece of work in $30$ days. $B$ and $C$ together can do it in $20$ days. $A$ starts the work and works on it for $5$ days,then $B$ takes over and works for $15$ days. Finally,$C$ finishes the work in $18$ days. The number of days in which $C$ alone can do the work is (in days):

$A$ and $B$ undertook to do a piece of work for $Rs. 4500$. $A$ alone could do it in $8$ days and $B$ alone in $12$ days. With the assistance of $C$,they finished the work in $4$ days. Then,$C$'s share of the money is (in $Rs.$)