Numerical Appli...

$A, B$ and $C$ complete a piece of work in $25, 20$ and $24$ days respectively. All work together for $2$ days and then $A$ and $B$ leave the work . $C$ works for next $\displaystyle8\frac{3}{5}$ days and then $A$ along with $D$ join $C$ and they all finish the work in next three days. In how many days $D$ alone can complete the whole work ?

Two pipes can fill a tank in $25$ and $30$ minutes respectively and a waste pipe can empty 3 gallons per minute. All the three pipes working together can fill the tank in $15$ minutes. The capacity of the tank is:

A can complete a piece of work in $18$  days, B in $20$  days and C in $30$  days. B and C together start the work and forced to leave after  $2$ days. the time taken by A alone to complete the remaining work is 

$A$ can do a work in $15$ days and $B$ can do the same work in $20$ days, if $A$ and $B$ has done work for $4$ days together, the fraction of work left?

Two pipes can fill an empty tank separately in  $24$  minutes  and  $40$ minutes respectively and a third pipe can empty  $30$  gallons of water per minute. If all the three pipes are open, empty tanks becomes full in one hour. The capacity of tank (in gallons) is 

A tap A can fill a cistern in $8$ hours while tap B can fill it in $4$ hours. In how much times will the cistern be filled if both A and B are opened together?

In half of a 600 square meters field, a fanner sowed ragi, in one-third of the remaining, he sowed coconut and in one-fourth of the left over, he sowed groundnut. He left half of the remaining land uncultivated. In one-third of the land still left, he dug a well, utilising the remaining land for growing orchids. What fraction of the total land is he using for orchid cultivation?

If a pipe fills the tank in $10$ minutes, how much minutes it will take to half fill the tank in we connect two pipes?

If $15$ men complete a task in $3$ days, how many days will  $9$  men take to complete it?

If $6$ painters can complete $9$ drawing in $5$ hours then, what is relation between no. of painters and no. of drawings if no. of hours is constant?