$A$ and $B$ can do a piece of work in $12$ days, $B$ and $C$ in $8$ days, and $C$ and $A$ in $6$ days. How long would $B$ take to do the same work alone? (in days)

$A, B$ and $C$ together earn $Rs. 2700$ in $18$ days. $A$ and $C$ together earn $Rs. 940$ in $10$ days. $B$ and $C$ together earn $Rs. 1520$ in $20$ days. Find the daily earning of $C$ (in $Rs.$).

$A$ man,a woman,and a boy can together complete a piece of work in $3$ days. If a man alone can do it in $6$ days and a boy alone in $18$ days,how long will a woman alone take to complete the work? (in days)

$A$ and $B$ can do a job in $6$ and $12$ days,respectively. They began the work together,but $A$ leaves after $3$ days. Then,the total number of days needed for the completion of the work is:

$A, B$ and $C$ can complete a piece of work in $15, 30$ and $40$ days respectively. They started the work together,but $A$ left $2$ days before the completion of the work and $B$ left $4$ days before the completion of the work. In how many days was the work completed?

Rohan and Mohit can build a wall in $8 \, days$,Mohit and Vikas can build the same wall in $10 \, days$,and Vikas and Rohan can build the same in $12 \, days$. In how many days can all three complete the same wall while working together?