$P$ can do a piece of work in $9$ days. $Q$ is $50\%$ more efficient than $P$. The number of days it takes for $Q$ to do the same piece of work is

$3$ men and $2$ women can do a piece of work in $15$ days. $2$ men and $3$ women can do the same work in $18$ days. The number of days to be taken by $1$ man and $1$ woman to do the work is:

$A, B$ and $C$ can do a piece of work individually in $8, 12$ and $15$ days,respectively. $A$ and $B$ start working,but $A$ quits after working for $2$ days. After this,$C$ joins $B$ until the completion of the work. In how many days will the work be completed?

$A$ 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 $minutes$)

$2$ men and $3$ women together or $4$ men together can complete a piece of work in $20$ days. $3$ men and $3$ women will complete the same work in (in days):

$A$ and $B$ together can do a piece of work in $30$ days. $B$ and $C$ together can do it in $20$ days. $A$ starts the work and works on it for $5$ days,then $B$ takes over and works for $15$ days. Finally,$C$ finishes the work in $18$ days. The number of days in which $C$ alone can do the work is (in days):