$A$ and $B$ together can do a piece of work in $9$ days. If $A$ does thrice the work of $B$ in a given time,the time $A$ alone will take to finish the work is (in days)

$3$ persons undertake to complete a piece of work for $Rs. 1,200$. The $first$ person can complete the work in $8$ days,the $second$ person in $12$ days,and the $third$ person in $16$ days. They complete the work with the help of a $fourth$ person in $3$ days. What does the $fourth$ person get? (in $Rs.$)

How many men will be required to plough $100 \, acres$ of land in $10 \, days$ if $10 \, men$ require $8 \, days$ to plough $20 \, acres$ of land?

$A$ and $B$ can do a piece of work in $20$ days and $12$ days,respectively. $A$ started the work alone and then after $4$ days $B$ 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?

If $4$ men or $8$ women can do a piece of work in $15$ days,in how many days can $6$ men and $12$ women do the same piece of work?