60. World Population Growth After its fastest rate of growth ever during the 19805 and 19905, the rate of growth of world population is expected to slow dramatically in the twenty-rst century. The function G (t) = 1536-0-21?\" gives the projected annual average percent population growth per decade in the tth decade, with t = 1 corresponding to 2000. a. What will the projected annual average population growth rate be in 2020 (t = 3)? b. How fast will the projected annual average population growth rate be changing in 2020