$A$ can complete a piece of work in $40$ days. He starts working,but having some other engagements,he leaves after $5$ days. Thereafter,$B$ completes the remaining work in $21$ days. How many days would $A$ and $B$ take to complete this work working together?

$A$ can finish a work in $18$ days and $B$ can do the same work in $15$ days. $B$ worked for $10$ days and left the job. In how many days can $A$ alone finish the remaining work?

Bansal,Gupta,and Singhal together can complete a work in $4 \, \text{days}$. If Bansal and Gupta together can complete the work in $4 \frac{4}{5} \, \text{days}$,and Gupta and Singhal together can do it in $8 \, \text{days}$,then Gupta alone can complete the work in (in $\text{days}$):

$A$ can complete a work in $6 \, days$ while $B$ can complete the same work in $12 \, days$. If they work together and complete it,the portion of the work done by $A$ is:

Kim can do a work in $3 \, \text{days}$ while David can do the same work in $2 \, \text{days}$. Both of them finish the work together and get $Rs. 150$. What is the share of Kim? (in $Rs.$)

$B$ would have taken $10 \, \text{hours}$ more than what $A$ would have taken to complete a task if each of them worked alone. Working together they can complete the task in $12 \, \text{hours}$. How many $\text{hours}$ would $B$ take to do $50 \%$ of the task?