$A$ and $B$ can together complete a task in $18$ hours. After $6$ hours, $A$ leaves. $B$ takes $36$ hours to finish the rest of the task. How many hours would $A$ have taken to do the task if he worked alone?

$A$ can do a piece of work in $8$ days. $A$ undertook it for $Rs. 320$. With the help of $B$,he finishes the work in $6$ days. $B$'s share is (in $Rs.$):

$B$ would have taken $10 \, \text{hours}$ more than what $A$ would have taken to complete a task if each of them worked alone. Working together they can complete the task in $12 \, \text{hours}$. How many $\text{hours}$ would $B$ take to do $50 \%$ of the task?

$A$ and $B$ complete a job in $12 \text{ days}$,while $A, B$,and $C$ can complete it in $8 \text{ days}$. $C$ alone will finish the job in (in $\text{days}$):

$A$ can finish a work in $18$ days and $B$ can do the same work in $15$ days. $B$ worked for $10$ days and left the job. In how many days can $A$ alone finish the remaining work?

$7$ men can complete a piece of work in $12$ days. How many additional men will be required to complete double the work in $8$ days?