$A$ does half as much work as $B$ in $\frac{3}{4}$ of the time. If together they take $18$ days to complete a work,then how much time shall $B$ take to complete it? (in days)

$A$ certain job was assigned to a group of men to do in $20$ days. But,$12$ men did not turn up for the job and the remaining men did the job in $32$ days. The original number of men in the group was:

$A$ tyre has two punctures. The first puncture alone would have made the tyre flat in $9 \,minutes$ and the second alone would have done it in $6 \,minutes.$ If air leaks out at a constant rate,how long does it take both the punctures together to make it flat? (in $minutes$)

$A$ track of $100\, m$ can be built by $7\, men$ or $10\, women$ in $70\, days.$ How many days will $14\, men$ and $20\, women$ take to build a track of $600\, m$?

$10$ women can complete a work in $7$ days and $10$ children take $14$ days to complete the work. How many days will $5$ women and $10$ children take to complete the work?

$A$ and $B$ can do a job in $6$ and $12$ days,respectively. They began the work together,but $A$ leaves after $3$ days. Then,the total number of days needed for the completion of the work is: