$A$ can complete a piece of work in $12$ days. $B$ is $60\%$ more efficient than $A$. The number of days that $B$ will take to complete the same work 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 $Rs.$)

$A$ takes three times as long as $B$ and $C$ together to do a job. $B$ takes four times as long as $A$ and $C$ together to do the work. If all the three,working together,can complete the job in $24$ days,then the number of days $A$ alone will take to finish the job is:

$A$ can do a certain job in $12$ days. $B$ is $60\%$ more efficient than $A$. How many days would $B$ alone take to do the same job?

$A$ can do a piece of work in $30 \text{ days}$ while $B$ can do it in $40 \text{ days}$. $A$ and $B$ working together can do it in (in $\text{days}$)

$A$ and $B$ can do a piece of work in $20$ days and $12$ days respectively. $A$ started the work alone and then after $4$ days $B$ joined him until the completion of the work. How long did the work last? (in days)