$7$ 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?

How many $days$ will $1648$ persons take to construct a dam,if $721$ persons can build the same in $48$ days?

$P$ can do $\left(\frac{1}{4}\right)$ of the work in $10$ days. $Q$ can do $40\%$ of the work in $40$ days and $R$ can do $\left(\frac{1}{3}\right)$ of the work in $13$ days. Who will complete the work first?

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?

$A$ and $B$ working separately can do a piece of work in $9$ and $12$ days,respectively. If they work for a day alternatively with $A$ beginning,the work would be completed in (in 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?