Rajan does $\frac{7}{11}$ of a work in 21 days. How many more days will he take to complete the work?

P, Q and R can complete a work in 12, 9 and 15 days respectively. Working together, they will complete the same work in:

A, B and C can do a work in 10, 12 and 15 days respectively. In how many days will the work be completed if B is assisted by both A and C on every third day ?

Find in whichever condition/conditions filling of water tank is/are possible :

A. One tap filling the tank in 2 liter / minute.

B. One tap filling the tank in 15 liter / minute and one tap emptying the tank with speed 1 liter / minute.

C. Two tap filling the tank with uniform speed of 4litre/minute and one tap emptying the tank with speed of 500 ml / sec.

D. One tap filling the tank in 2 liter / minute and one tap emptying the tank with speed 4 liter / minute.

Choose the correct answer from the options given below:

'A' can build up a structure in 8 days and 'B' can break it in 3 days. 'A' worked building for 4 days and then 'B' joined and start breaking while 'A' kept building for another 2 days. In how many days will 'A' alone build up the remaining part of the structure?

A and B can do a piece of work in 12 days; B and C together can do it in 15 days. If A is twice as good a workman as C, find the number of days in which B alone can do the work?

A is twice as good a workman as B and together they finish a piece of work in 14 days. The number of days that A alone will take to finish the work is: