$x$ number of men can finish a piece of work in $30$ days. If there were $6$ men more,the work could be finished in $10$ days less. The actual number of men is

$A$ and $B$ can complete a piece of work in $45$ and $40$ days,respectively. They began the work together,but $A$ leaves after some days and $B$ completed the remaining work in $23$ days. After how many days did $A$ leave?

$A$ and $B$ together can complete a work in $10$ days. They started together,but $A$ left after $2$ days and the remaining work was completed by $B$ in $12$ days. In how many days can $A$ complete the entire work while working alone?

$2$ 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?

$A, B$ and $C$ can complete a piece of work in $24, 6$ and $12 \text{ days}$ respectively. Working together,they will complete the same work in (in $\text{days}$):

$A$ takes $10\, \text{days}$ less than the time taken by $B$ to finish a piece of work. If both $A$ and $B$ can do it in $12\, \text{days}$, then the time taken by $B$ alone to finish the work is (in $\text{days}$)