Approximately 28 million people worldwide had paid subscriptions for digital music services in 2013. This was an increase from 8 million people in 2010. [3.7] Data: ifpi.org a) Graph the data and determine an equation for the related line. Let d represent the number of people with paid digital music service subscrip- tions and t the number of years after 2010. b) Use the equation of part (a) to estimate the number of people with paid digital music service subscriptions in 2016.