If $10$ men or $20$ boys can make $260$ shirts in $20$ days,then how many shirts will be made by $8$ men and $4$ boys in $20$ days?

$A, B$ and $C$ can do a piece of work in $16, 32$ and $48$ days,respectively. They started working together,but $C$ left after working $4$ days and $B$ left $2$ days before the completion of the work. The total number of days taken for the completion of the work was (in days):

Four examiners can examine a certain number of answer papers in $10$ days by working for $5$ hours a day. For how many hours in a day would $2$ examiners have to work in order to examine twice the number of answer papers in $20$ days?

$12$ men complete a work in $9$ days. After they have worked for $6$ days,$6$ more men join them. How many days will they take to complete the remaining work?

$28$ men can complete a piece of work in $15 \, \text{days}$ and $15$ women can complete the same piece of work in $24 \, \text{days}$. What is the respective ratio between the amount of work done by $30$ men in $1 \, \text{day}$ and the amount of work done by $18$ women in $1 \, \text{day}$?

$A$ certain sum of money is sufficient to pay wages for $21$ days of $X$ or $28$ days of $Y$. The money is sufficient to pay the wages of both for ........ days.