Twelve men can do a piece of work in $15$ days. How many are required to complete a work which is three and a half times the original work in $10$ days.

Working individually, $A$ and $B$ can complete a piece of work in $30$ days and $45$ days respectively. If $B$ joins $A$ after some days and the whole work is completed in $20$ days from the beginning, after how many days does $B$ join $A$ ?

If $10$ men or $15$ women can do a work in $20$days, then in how many days $4$ men and $6$ women can do the same work?

Gautham and Karthik can do a piece of work in $10$ days and $20$ days, respectively. With the help of Nilesh, they can completed the whole work in $5$ days. In how many days can Nilesh alone complete the work?

$A$ and $B$ can do a work in $2\frac{2}{5}$ days. $B$ alone can do the work in $6$ days. They will get $₹40,000$ for completing the work. But with the help of $C$, they completed the work in $1\frac{1}{2}$ days, then what is the share of $C$?

$A$ is twice as efficient as $B$ and they together can complete a piece of work in $24$ days. Find the number of days that $A$ alone takes to complete the work.

Malini can do a piece of work in $20$ days, whereas Shalini can do it in $25$ days. Shalini started the work and after $5$ days, Malini joined her. They together completed the remaining work. How many days did they take to complete the whole work?

Working individually, $A, B$ and $C$ can finish a piece of work in $16$ days, $20$ days and $30$ days respectively. In how many days can $A, B$ and $C$ can together complete a work which is $3\frac{1}{2}$ times of their previous work?