$A$ and $B$ can do a job in $6$ and $12$ days,respectively. They began the work together,but $A$ leaves after $3$ days. Then,the total number of days needed for the completion of the work is:

$A$ and $B$ working separately can do a piece of work in $9$ and $15 \, \text{days}$ respectively. If they work on alternate days beginning with $A$,then the work will be completed in how many days?

$A$ takes $10\, \text{days}$ less than the time taken by $B$ to finish a piece of work. If both $A$ and $B$ can do it in $12\, \text{days}$, then the time taken by $B$ alone to finish the work is (in $\text{days}$)

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)

$A$ can do a work in $20 \, days$ and $B$ in $40 \, days$. If they work on it together for $5 \, days$,then the fraction of the work that is left is:

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?