$2$ 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):

If $8$ men or $10$ women can do a piece of work in $50$ days,in what time will $28$ men and $15$ women do it? (in days)

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

$P, Q$ and $R$ undertake to do a work for $Rs. 707$. $P$ and $Q$ together do $\frac{5}{7}$ of the work and the rest is done by $R$ alone. How much should $R$ get? (in $Rs.$)

Machine $P$ can print one lakh books in $8$ hours,machine $Q$ can print the same number of books in $10$ hours,while machine $R$ can print them in $12$ hours. All the machines are started at $9.00$ a.m. while machine $P$ is closed at $11.00$ a.m. and the remaining two machines complete the work. Approximately at what time will the work be finished?