Throughout history, the search for salt has played an important role in society. Where it was scarce, salt was traded ounce for ounce with gold. Rome's major highway was called via the salaries that are the Salt Road. Along the road, Roman soldiers transported salt crystals from the salt flats at Ostia up the Tiber River. In return, they received a solarium or salary, which was literally money paid to soldiers to buy salt. The old saying worth their salt' which means to be valuable derives from the custom of payment during the Empire.
A train 75 meters long is running with a speed of 20 km /hr. it will pass a standing man in -
