If $8$ men or $10$ women can do a piece of work in $50$ days,in what time will $28$ men and $15$ women do it? (in days)

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

$A$ can finish a work in $24 \, days$,$B$ in $9 \, days$,and $C$ in $12 \, days$. $B$ and $C$ start the work but are forced to leave after $3 \, days$. The remaining work was done by $A$ in (in $days$):

$A$ does $\frac{1}{5}$ of a work in a $week$. $B$ finishes the same in a fortnight. $B$ starts the work and works only for $3$ days. Thereafter,$A$ completes the job. In how many days will $A$ finish the remaining work?

While working $7$ hours a day,$A$ alone can complete a piece of work in $6$ days and $B$ alone in $8$ days. In what time would they complete it together,working $8$ hours a day? (in days)

$A$ and $B$ can complete a piece of work in $18$ days; $B$ and $C$ in $24$ days; $C$ and $A$ in $36$ days. $A$ alone can complete the work in (in days):