Question: How many copies did back in black sell?
Disambiguated questions and answers: question: About how many copies did back in black sell worldwide?
By 13 December 2007, about how many certified copies did back in black sell in the US?
About how many certified copies did back in black sell in AC/DC's native Australia?
About how many certified copies did back in black sell in the UK?
answer: 50 million copies
50 million
22 million
22× multi-platinum
22 million American sales
180,000
3× Platinum
600,000
Natural Questions answer: an estimated 50 million (from the Wikipedia article "Back in Black")