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.
It is true that everybody and everyone refers to everybody and everyone in a group of people and everything refers to everything in a group of things. Even so, they are still perceived individually or as a totality, so the singular verb form is still maintained: