How many years would it take to listen to nine trillion cds?

Music CDs can hold up to 80 minutes of music, but many contain far less. To make the math easier, let's say there's only an hour's worth of music on a CD. If you listen to CDs continuously without breaks, you will be listening to 9 trillion, or 9E12 hours of music. How many hours are in a year (an Earth year, of course)? Well, 365 days per year times 24 hours per day equals 8760 or 8.76E3 hours per year. Hence, 9E12 hours divided by 8.76E3 hours per year equals 1,027,397,260 years, a bit longer than 1.027 billion years.