A certain number of persons can complete a work in 54 days. If there were 15 persons less, it would take 18 days more for the work to be completed. Initially, the number persons is:
A buys an article for Rs.900 and sells it to B at a profit of 25%. B sells it to C, who sells it for Rs.1,350, at a loss of 10%. What profit percent (to the nearest integer) did B make?
The time taken by a boat to go a certain distance upstream is twice the time taken by it to go the same distance downstream. If the speed of the stream is 3 km/h, then how much time (in hours) will the boat take to go 52 km upstream?