$A$ 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?

$A$ labourer can do a job in $36 \text{ hours}$. After $9 \text{ hours}$,he takes a break. What fraction of the job is yet to be done?

Sita takes twice as much time as Gita to complete a work and Rita does it in the same time as Sita and Gita together. If all three working together can finish the work in $6$ days,then the time taken by each of them to finish the work is (in days):

$A$ and $B$ together can complete a work in $10$ days. They started together,but $A$ left after $2$ days and the remaining work was completed by $B$ in $12$ days. In how many days can $A$ complete the entire work while working alone?

$6$ men or $12$ women can do a piece of work in $20$ days. In how many days can $8$ men and $16$ women do twice as big as this work?

$4$ men and $6$ women complete a work in $8$ days,$2$ men and $9$ women also complete the same work in $8$ days. In how many days will $18$ women complete the work?