$A$ can complete a piece of work in $40$ days. He starts working,but having some other engagements,he leaves after $5$ days. Thereafter,$B$ completes the remaining work in $21$ days. How many days would $A$ and $B$ take to complete this work working together?

If $A$ and $B$ together can complete a piece of work in $15$ days and $B$ alone in $20$ days,in how many days can $A$ alone complete the work?

The total number of men,women,and children working in a factory is $18$. They earn $Rs. 4000$ in a day. If the sum of the wages of all men,all women,and all children is in the ratio $18: 10: 12$,and the wages of an individual man,woman,and child are in the ratio $6: 5: 3$,then how much does a woman earn in a day? (in $Rs.$)

There is sufficient food for $400$ men for $31$ days. After $28$ days,$280$ men leave the place. For how many days will the rest of the food last for the rest of the men? (in days)

$A$ can do a work in $12$ days. When he had worked for $3$ days,$B$ joined him. If they complete the work in $3$ more days,in how many days can $B$ alone finish the work?

$A$ 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 $minutes$)