The marked price of an article is Rs.1,280. If a shopkeeper sold the article at 12% profit after giving 30% discount, then the cost price of the article is:
8 children and 12 men complete a certain piece of work in 9 days. If each child takes twice the time taken by a man to finish the work, in how many days will 12 men finish the same work ?
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: