Numerical Appli...

It takes pump (A) $$4$$ hours to empty a swimming pool. It takes pump (B) $$6$$ hours to empty the same swimming pool. If the two pumps are started together, at what time will the two pumps have emptied $$50$$% of the water in the swimming pool?

The average (mean) number of children per family in the village is approximately.

Seven person $$P_1,P_2......, P_7$$ initially seated at chairs $$C_1,C_2,.....C_7$$ respectively.They all left there chairs simultaneously for hand wash. Now in how many ways they can again take seats such that no one sits on his own seat and $$P_1$$, sits on $$C_2$$ and $$P_2$$ sits on $$C_3$$ ?

If $$m$$ denotes the number of $$5$$ digit numbers if each successive digits are in their descending order of magnitude and $$n$$ is the corresponding figure. When the digits and in their ascending order of magnitude then $$(m-n)$$ has the value

It 10 men or 20 women or 40 children can do a piece of work in 7 months, then 5 men, 5 women and 5 children together can do half of the work in :

Raman can do a work in $$5$$ days, Jatin can do the same work in $$7$$ days and Sachin can do the same work in $$9$$ days. If they do the same work together and they are paid Rs. $$2860$$, then what is the share (in Rs.) of Raman?

What was the average number of children taking swim lessons from 1990 to 1995?

If four men working at the same rate can do $$2/3$$ of a job in $$40$$ minutes it take one man working at this rate to do $$2/5$$ of the job takes how many minutes?

A library has $$'a'$$ copies of one book, $$'b'$$ copies of each of two books, $$'c'$$ copies of each of three books, and single copy each of $$'d'$$. The total number of ways in which these books can be arranged in a row is

If $$18$$ pumps can raise $$2170$$ tonnes of water in $$10$$ days working $$7$$ hours  a day then in how many days will $$16$$ pumps raise $$1736$$ tonnes of water working $$9$$ hours a day