$A$ contractor has the target of completing a work in $40 \text{ days}$. He employed $20$ persons who completed $\frac{1}{4}$ of the work in $10 \text{ days}$ and left. The number of additional persons he has to employ to finish the remaining part of the work as per the target is:

$A, B$ and $C$ do a job in $6$ days,$12$ days and $15$ days respectively. After $\frac{1}{8}$ of the work is completed,$C$ leaves the job. The rest of the work is done by $A$ and $B$ together. What is the time taken to finish the remaining work? (in days)

$P, Q, R$ are employed to do a work for $Rs. 5750$. $P$ and $Q$ together finished $\frac{19}{23}$ of the work,and $Q$ and $R$ together finished $\frac{8}{23}$ of the work. The wage of $Q$ (in rupees) is:

$A,$ $B,$ and $C$ have to type $506$ pages to finish an assignment. $A$ can type a page in $12$ minutes,$B$ in $15$ minutes,and $C$ in $24$ minutes. If they divide the task into three parts so that all three of them spend an equal amount of time typing,what is the number of pages that $B$ should type?

$A$ and $B$,working together,can complete a piece of work in $12$ days. $B$ and $C$ working together can complete the same piece of work in $16$ days. $A$ worked at it for $5$ days and $B$ worked at it for $7$ days. $C$ finished the remaining work in $13$ days. How many days would $C$ alone take to complete it?

$A$ can do $\frac{1}{4}$ of a work in $10$ days. $B$ can do $\frac{1}{3}$ of the work in $20$ days. In how many days can both $A$ and $B$ together do the work?