Numerical Appli...

A and B together can do a job in $$2$$ days; B and C can do it in four days; and A and C in $$2\dfrac{2}{5}$$ days. The number of days required for A to do the job alone is:

$$A$$ and $$B$$ together can finish a work in $$30$$ days. They worked on it for $$20$$ days and then $$B$$ left the work. The remaining work was done by $$A$$ alone in $$20$$ days more. In how many days can $$A$$ alone finish the work?

$$A$$ and $$B$$ together can complete a work in $$3$$ days. They start together but, after $$2$$ days, $$B$$ left the work. If the work is completed after $$2$$ more days, $$B$$ alone could do the work in

$$8$$ taps of the same size fill a tank in $$27$$ minutes. If two taps go out of order, how long would the remaining taps take to fill the tank?

$$12$$ workers can complete a piece of work in $$10$$ days. If the number of workers are reduced to $$\dfrac {1}{3}rd$$ of the original number, then how many more days would be required to complete the same work?

If $$^{n + 1}{C_3} = 4\,{\,^n}{C_2}$$ then $$n=$$

A can do a piece of work in $$80 days $$.He work  at it for $$10$$ days and then $$B$$ alone finishes the work in $$42$$ day.In how much time will A and B working together,finish the work?

$$3$$ letters are posted in $$5$$ letters boxes. If all the letters are not posted in the same box, then number of ways of posting is

A _____ is an arrangement of all or part of set of object in a definite order.

$$8$$ men can dig a pit in $$20$$ days. If a man works one and a half as much again as a boy, then $$4$$ men and $$8$$ boys can dig it in