$A$ can do a work in $20 \, days$ and $B$ in $40 \, days$. If they work on it together for $5 \, days$,then the fraction of the work that is left is:

$A$ contract is to be completed in $92$ days and $234$ men were set to work,each working $16$ hours a day. After $66$ days,$\frac{4}{7}$ of the work is completed. How many additional men may be employed,so that the work may be completed in time,each man now working $18$ hours a day?

$A$ and $B$ can complete a piece of work in $30 \text{ days}$,$B$ and $C$ can complete the same work in $20 \text{ days}$,and $A$ and $C$ can complete it in $15 \text{ days}$. If all of them work together,the time taken to complete the work will be? (in $days$)

$A$ and $B$ can do a piece of work in $10$ days. $B$ and $C$ can do it in $12$ days. $A$ and $C$ can do it in $15$ days. How long will $A$ take to do it alone? (in days)

$P, Q$ and $R$ undertake to do a work for $Rs. 660$. $P$ and $Q$ together do $8/11$ of the work and the rest is done by $R$ alone. How much should $R$ get? (in $Rs.$)

$A$ and $B,$ working separately,can complete a piece of work in $9$ and $12$ days,respectively. If they work for a day alternately,$A$ beginning,in how many days will the work be completed?