$A$ is $20\%$ more efficient than $B$. If $B$ alone can complete a piece of work in $12$ days,then $A$ alone can complete the same work in how many days?

$P$ and $Q$ can do a piece of work in $30$ and $40$ days respectively. They began the work together,but $P$ left after some days and $Q$ finished the remaining work in $12$ days. After how many days did $P$ leave?

Bindal can finish a work in $10$ days. Jindal is twice as efficient as Bindal. If they work together,in how many days will the work be completed?

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)

$3$ women and $18$ children together take $2$ days to complete a piece of work. How many days will $9$ children alone take to complete the piece of work,if $6$ women alone can complete the piece of work in $3$ days?

$10$ men can finish a piece of work in $10$ days,whereas it takes $12$ women to finish it in $10$ days. If $15$ men and $6$ women undertake to complete the work,how many days will they take to complete it?