Kamal can do a work in $15$ days. Sita is $50$ percent more efficient than Kamal in doing the work. In how many days will Sita do that work?

$P$ can do a piece of work in $9$ days. $Q$ is $50\%$ more efficient than $P$. The number of days it takes for $Q$ to do the same piece of work is

One man,$3$ women,and $4$ boys can do a work in $96$ hours,$2$ men and $8$ boys can do it in $80$ hours,and $2$ men and $3$ women can do it in $120$ hours. In how many hours can it be done by $5$ men and $12$ boys? (in hours)

Sunil completes a work in $4$ days,whereas Dinesh completes the work in $6$ days. Ramesh works $1 \frac{1}{2}$ times as fast as Sunil. The three together can complete the work in (in days):

$P, Q$ 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 $Rs.$)

$7$ men can complete a piece of work in $12$ days. How many additional men will be required to complete double the work in $8$ days?