An infinite geometric series has first term 328 and a sum of 2009. What is its common ratio?
Sum of an infinite series = first term / ( 1 -common ratio )
2009 = 328/ (1 -r) rearrange as
2009 (1 -r) = 328
2009 - 2009r = 328
2009 - 328 = 2009r
1681 = 2009 r
r = 1681/2009 = 41/49
+285 
