If $A$ and $B$ together can complete a piece of work in $15$ days and $B$ alone in $20$ days,in how many days can $A$ alone complete the work?

$x$ number of men can finish a piece of work in $30$ days. If there were $6$ men more,the work could be finished in $10$ days less. The actual number of men is

$A$ 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:

Machine $P$ can print one lakh books in $8$ hours,machine $Q$ can print the same number of books in $10$ hours,while machine $R$ can print them in $12$ hours. All the machines are started at $9.00$ a.m. while machine $P$ is closed at $11.00$ a.m. and the remaining two machines complete the work. Approximately at what time will the work be finished?

$A$ and $B$ can do a piece of work in $8$ days,$B$ and $C$ can do the same work in $12$ days,and $A, B,$ and $C$ together complete it in $6$ days. The number of days required to finish the work by $A$ and $C$ together is:

If $6$ men and $8$ boys can do a piece of work in $10$ $days$ while $26$ men and $48$ boys can do the same in $2$ $days,$ the time taken by $15$ men and $20$ boys in doing the same type of work will be (in $days$)