$7$ 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?

$P$ and $Q$ complete a certain work in $30 \, days$,$Q$ and $R$ in $40 \, days$,while $R$ and $P$ in $60 \, days$. How long will they take to finish it together? (in $days$)

$7$ 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?

If $A$ had worked alone, he would have taken $63 \, \text{hours}$ to complete the task. If $A$ and $B$ work together, they finish the task in $36 \, \text{hours}$. If they are paid $Rs. 5,950$ for the work, what is $B$'s share?

$2$ men and $3$ women together or $4$ men together can complete a piece of work in $20$ days. $3$ men and $3$ women will complete the same work in (in days):

Hemant decided to build a farmhouse in $40$ days. He employed $100$ men in the beginning and $100$ more after $35$ days and completed the construction in the stipulated time. If he had not employed the additional men,how many days behind schedule would it have been finished? (in days)