600, 125, 30,?, 7.2, 6.44, 6.288

Series pattern
600/5 + 5 = 125
125/5 + 5 = 30
30/5 + 5 = 11
Should come in place of '?'
11/5 + 5 = 7.2
7.5/5 + 5 = 6.44
6.44/5 + 5 = 6.288