$6$ 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?

$A$ work can be completed by $P$ and $Q$ in $12$ days,$Q$ and $R$ in $15$ days,and $R$ and $P$ in $20$ days. In how many days can $P$ alone finish the work?

$A, B$ and $C$ are employed to do a piece of work for $Rs. 575$. $A$ and $C$ are supposed to finish $\frac{19}{23}$ of the work together. The amount to be paid to $B$ is (in $Rs.$)

$2$ men and $1$ woman can do a piece of work in $14$ days,while $4$ women and $2$ men can do the same work in $8$ days. If a man gets $Rs. 90$ per day,what should be the wages per day of a woman? (in $Rs.$)

$A$ can complete a work in $m$ days and $B$ can complete it in $n$ days. How many days will it take to complete the work if both $A$ and $B$ work together?

$A$ and $B$ can complete a piece of work in $30 \text{ days}$,$B$ and $C$ in $40 \text{ days}$,while $C$ and $A$ in $60 \text{ days}$. $A, B, C$ together can complete the work in (in $\text{days}$):