$A$ can finish a work in $18$ days and $B$ can do the same work in half the time taken by $A$. Then,working together,what part of the same work can they finish in a day?

$A$ job can be completed by $12$ men in $12$ days. How many extra days will be needed to complete the job if $6$ men leave after working for $6$ days?

$A, B$ and $C$ can 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. The total time taken to finish the work is (in days):

$A$ alone would take $27 \, \text{days}$ more to complete the job than if both $A$ and $B$ worked together. If $B$ worked alone, he would take $3 \, \text{days}$ more to complete the job than $A$ and $B$ working together. What time would they take if both $A$ and $B$ worked together? (in $\text{days}$)

$3$ 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 $Rs.$)

If $A$ and $B$ together can complete a piece of work in $15$ days and $B$ alone in $20$ days,in how many days can $A$ alone complete the work?