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?

$A$ and $B$ can complete a piece of work in $6$ days,and $A$ alone can complete it in $9$ days. The time taken by $B$ alone to complete the work is (in days):

The first man alone can complete a work in $7$ days. The second man alone can do this work in $8$ days. If they work together to complete this work in $3$ days with the help of a boy,and the total payment is $Rs. 1400$,how should the money be divided among them?

$A, B$ and $C$ can complete a piece of work in $24, 6$ and $12 \text{ days}$ respectively. Working together,they will complete the same work in (in $\text{days}$):

$A, B$ and $C$ do a job in $6$ days,$12$ days and $15$ days respectively. After $\frac{1}{8}$ of the work is completed,$C$ leaves the job. The rest of the work is done by $A$ and $B$ together. What is the time taken to finish the remaining work? (in days)

How many men will be required to plough $100 \, acres$ of land in $10 \, days$ if $10 \, men$ require $8 \, days$ to plough $20 \, acres$ of land?