$A$ 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)

$A$ can do $\frac{1}{3}$ of a work in $5 \text{ days}$ and $B$ can do $\frac{2}{5}$ of the work in $10 \text{ days}$. In how many $\text{days}$ can both $A$ and $B$ together do the work?

Sister can bake $50$ cakes in $25$ hours. Sister and Mummy together can bake $75$ cakes in $15$ hours. How many cakes can Mummy bake in $15$ hours?

$A$ can do a piece of work in $12$ days and $B$ in $20$ days. If they together work on it for $5$ days and the remaining work is completed by $C$ in $3$ days, then in how many days can $C$ do the same work alone?

$A$ can do a work in $15\, days$ and $B$ in $20\, days.$ If they work on it together for $4\, days,$ then the fraction of the work that is left is

Sita takes twice as much time as Gita to complete a work and Rita does it in the same time as Sita and Gita together. If all three working together can finish the work in $6$ days,then the time taken by each of them to finish the work is (in days):