Ram,Rajan,and Rangan can do a certain work in $6, 12,$ and $24$ days respectively. In what time will they altogether do it? (in days)

$A$ contractor has the target of completing a work in $40 \text{ days}$. He employed $20$ persons who completed $\frac{1}{4}$ of the work in $10 \text{ days}$ and left. The number of additional persons he has to employ to finish the remaining part of the work as per the target is:

$A$ works thrice as good as $B$ and is,therefore,able to finish a piece of work in $60 \text{ days}$ less than $B$. Find the time in which they can complete it,working together (in $\text{days}$).

$A$ does half as much work as $B$ in $\frac{3}{4}$ of the time. If together they take $18 \text{ days}$ to complete a work,how much time shall $B$ take to do it alone? (in $\text{days}$)

$A$ can do a work in $6$ days and $B$ can do the same work in $5$ days. The contract for the work is of $Rs. 220$. How much shall $B$ get if both of them work together? (in $Rs.$)

$A$ and $B$ can do a piece of work in $12 \, \text{days}$ and $15 \, \text{days}$ respectively. They began to work together,but $A$ left after $4 \, \text{days}$. In how many more $days$ would $B$ alone complete the remaining work?