Andrew Su, CEO at brokerage Compass Global Markets said the average cost of producing gold in Australia, home to some of the world's biggest gold miners, has jumped from $500 an ounce in 2007 to over $1,000 an ounce this year.
Persons (plural) is a very formal word. We only use it in rather legalistic contexts: [notice in a lift] Any person or persons found in possession of illegal substances will be prosecuted.
Although typically words that identify more than one person, place, or thing are made plural in the English language, collective nouns are an exception. This unique class of nouns denotes a group of people, animals, objects, or concepts or ideas as a single entity. Comparing Countable, Mass and Collective Nouns