The second scroll is 4080 + 4080 / 2 = 4000 + 2040 = <<4080+4080/2=6120>>6120 years old.
The third scroll is 6120 + 6120 / 2 = 6120 + 3060 = <<6120+6120/2=9180>>9180 years old.
The fourth scroll is 9180 + 9180 / 2 = 9180 + 4590 = <<9180+9180/2=13770>>13770 years old.
The fifth scroll is 13770 + 13770 / 2 = 13770 + 6885 = <<13770+13770/2=20655>>20655 years old.
#### 20655