Verified answer

4 g in 5 days because that is one half-life, and half will be gone after a half-life.

Each subsequent 5 days, half of the remainder will disappear, so that by day 10, there will be just 2 g left, thn 1 g by day fifteen, etc.

DAYS...REMAINING

0.................8g

5............(a) 4g

10..........(b) 2g

15..........(c) 1g

20..........(d) 0.5g

25..........(e) 0.25g

50..........(f) 0.0078125g

(0.125g at 30d, 0.0635g at 35d,

0.03125g at 40d, 0.015625g at 45d)

a - 4g

b - 2g

c - 1g

d - 0.5g

e - 0.25g

f - 0.0078125g