A commodity market has a _________ structure, if there is one seller of the commodity, the commodity has no substitute, and entry into the industry by another firm is prevented.
The sum of the present ages of a father and his son is 60 yrs. Six years ago, fathers age was five times the age of the son. After 6 yrs, son's age will be
A piece of work can be done by 16 men in 8 days working 12 hours a day. How many men are needed to complete another work, which is three times the first one, in 24 days working 8 hours a day?