Shashi can do a piece of work in $20$ days. Tanya is $25\%$ more efficient than Shashi. The number of days taken by Tanya to do the same piece of work is

$4$ men and $6$ women together can complete a work in $8$ days,while $3$ men and $7$ women together can complete it in $10$ days. $20$ women working together will complete it in (in days):

$X$ and $Y$ can do a piece of work in $20$ days and $12$ days respectively. $X$ started the work alone and then after $4$ days $Y$ joined him until the completion of the work. How long did the work last? (in days)

$S, T$ and $U$ can complete a work in $40, 48$ and $60$ days respectively. They received $Rs. 10800$ to complete the work. They begin the work together,but $T$ left $2$ days before the completion of the work and $U$ left $5$ days before the completion of the work. $S$ completed the remaining work alone. What is the share of $S$ (in $Rs.$) from the total money?

$A$ and $B$ can do a job alone in $12 \text{ days}$ and $15 \text{ days}$ respectively. $A$ starts the work and after $6 \text{ days}$,$B$ also joins to finish the work together. For how many days did $B$ actually work on the job?

$4$ men and $6$ women together can complete a work in $8$ days,while $3$ men and $7$ women together can complete it in $10$ days. How many days will $20$ women working together take to complete the same work?