$A$ 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 job in $6 \, days$ and $A$ and $B$ can do it together in $2 \, days.$ How many $days$ will be taken by $B$ to do the job alone?

$A$ can do a piece of work in $12$ days and $B$ in $20$ days. If they together work on it for $5$ days and the remaining work is completed by $C$ in $3$ days, then in how many days can $C$ do the same work alone?

If $4$ men or $8$ women can do a piece of work in $15$ days,in how many days can $6$ men and $12$ women do the same piece of work?

$10$ men can cut $15$ trees in $2$ hours. If $2$ men leave the job,how many trees will be cut in $3$ hours?

$A, B$ and $C$ can do a piece of work in $16, 32$ and $48$ days,respectively. They started working together,but $C$ left after working $4$ days and $B$ left $2$ days before the completion of the work. The total number of days taken for the completion of the work was (in days):