After the period of how many days half moon can be seen?
Two men or 4 women or 8children can do a job in 10 days . In how many days 1man ,1women and 2 children can do the same job?
If 15 men or 24 women or 36 boys can do a piece of work in 12 days, working 8 hours a day, how many men must be associated with 12 women and 6 boys to do another piece of work 2.25 times in 30 days working 6 hours in a day?