$A, B$ and $C$ together can complete a piece of work in $30\, min$. $A$ and $B$ together can complete the same work in $50\, min$. $C$ alone can complete the work in? (in $min$)

$A$ and $B$ complete a job in $12 \text{ days}$,while $A, B$,and $C$ can complete it in $8 \text{ days}$. $C$ alone will finish the job in (in $\text{days}$):

$A$ and $B$ can do a work in $12$ days. $B$ and $C$ can do the same work in $15$ days. $C$ and $A$ can do the same work in $20$ days. How much time will $A, B,$ and $C$ take to complete the same work together (in days)?

Two workers $A$ and $B$ working together completed a job in $5$ days. If $A$ worked twice as efficiently as he actually did and $B$ worked $1/3$ as efficiently as he actually did,the work would have been completed in $3$ days. To complete the job alone,$A$ would require (in days):

If $3$ men or $5$ women can reap a field in $43$ days,how long will $5$ men and $6$ women take to reap it? (in days)

If $12$ men and $16$ boys can do a piece of work in $5 \, \text{days}$,and $13$ men and $24$ boys can do it in $4 \, \text{days}$,then the ratio of the daily work done by a man to that of a boy is: