Solve the following radical equation application problem and answer the question: do you have a cell phone? how long is your call? According to the Cellular Telecommunications Industry Association, the average length of a call for the years 1999, 2000, and 2001, were 2.38, 2.56, and 2.74 minutes, respectively. The average duration of a call can be approximated by the following algebraic equation l(t)=(t+5.5) , where l(t) represents the length of the call in minutes and t the years after 1999.