$A$ certain number of men complete a work in $160\, days$. If there were $38\, men$ more, the work could be finished in $20\, days$ less. How many men were originally there?

$A$ certain job was assigned to a group of men to do in $20$ days. But,$12$ men did not turn up for the job and the remaining men did the job in $32$ days. The original number of men in the group was:

$4$ men and $6$ women together can complete a work in $8$ days,while $3$ men and $7$ women together can complete it in $10$ days. $20$ women working together will complete it in (in 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?

$A$ team of $30$ men is supposed to do a work in $38$ days. After $25$ days,$5$ more men were employed and the work was finished one day earlier. How many days would it have been delayed if $5$ more men were not employed? (in days)

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