$A$ takes twice as much time as $B$ and $C$ takes thrice as much time as $B$ to finish a piece of work. Working together they can finish the work in $12$ days. The number of days needed for $A$ to do the work alone is:

$3$ persons undertake to complete a piece of work for $Rs. 1,200$. The $first$ person can complete the work in $8$ days,the $second$ person in $12$ days,and the $third$ person in $16$ days. They complete the work with the help of a $fourth$ person in $3$ days. What does the $fourth$ person get? (in $Rs.$)

$A$ can do a work in $10 \text{ days}$ and $B$ in $20 \text{ days}$. If they work together on it for $5 \text{ days}$,then the fraction of the work that is left is:

$A$ can finish a work in $24$ days,$B$ in $9$ days,and $C$ in $12$ days. $B$ and $C$ start the work but are forced to leave after $3$ days. The remaining work was done by $A$ in (in days):

Working efficiencies of $A$ and $B$ for completing a piece of work are in the ratio $3: 4$. The number of days taken by them to complete the work will be in the ratio:

$A,$ $B,$ and $C$ have to type $506$ pages to finish an assignment. $A$ can type a page in $12$ minutes,$B$ in $15$ minutes,and $C$ in $24$ minutes. If they divide the task into three parts so that all three of them spend an equal amount of time typing,what is the number of pages that $B$ should type?