Answer:
The answer to your question is:
Explanation:
a)
Data
half-life = 16.7 days
go from 1000 to 250 atoms
1000
500 1 half life
250 2 half lives
16.7 days ---------------- 1 half life
x ----------------- 2 half lives
x = (2 x 16.7) / 1
x = 33.4 days
b)
number of atoms = ?
after 9 half-lives
1000
500 1 half life
250 2 half lives
125 3 half lives
62.5 4 half lives
31.25 5 half lives
15.63 6 half lives
7.81 7 half lives
3.9 8 half lives
1.95 9 half lives
