$P, Q$ and $R$ undertake to do a work for $Rs. 660$. $P$ and $Q$ together do $8/11$ of the work and the rest is done by $R$ alone. How much should $R$ get? (in $Rs.$)

If $5$ men and $3$ boys can reap $23 \text{ hectares}$ in $4 \text{ days}$ and if $3$ men and $2$ boys can reap $7 \text{ hectares}$ in $2 \text{ days}$,how many boys must assist $7$ men in order that they may reap $45 \text{ hectares}$ in $6 \text{ days}$?

Subhash can copy $50$ pages in $10$ $h$,Subhash and Prakash can copy $300$ pages in $40$ $h$. In how much time can Prakash copy $30$ pages? (in $h$)

$A$ man,a woman,and a boy can complete a job in $3, 4,$ and $12$ days respectively. How many boys must assist $1$ man and $1$ woman to complete the job in $\frac{1}{4}$ of a day?

$2$ 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 $Rs.$)

$6$ 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?