$A$ can do a work in $12 \, days$. When he had worked for $3 \, days$,$B$ joined him. If they complete the work in $3$ more $days$,in how many $days$ can $B$ alone finish the work?

$A$ can do a piece of work in $120$ days and $B$ can do it in $150$ days. They work together for $20$ days. Then $B$ leaves and $A$ alone continues the work. After $12$ days,$C$ joins $A$ and the work is completed in $48$ days more. In how many days can $C$ do it if he works alone?

$A$ and $B$ can do a job together in $7$ days. $A$ is $1\frac{3}{4}$ times as efficient as $B$. The same job can be done by $A$ alone in (in days):

$A$ and $B$ working separately can do a piece of work in $9$ and $12$ days,respectively. If they work for a day alternatively with $A$ beginning,the work would be completed in (in days):

$A$ can do $50\%$ of the job in $16$ days,$B$ can do $\frac{1}{4}^{th}$ of the job in $24$ days. In how many days can they do $\frac{3}{4}^{th}$ of the job working together?

$2$ men and $5$ women can finish a piece of work in $12$ days. $5$ men and $2$ women can finish the same work in $9$ days. In how many days can $3$ women finish the same work?