Answer:
S(t) = 600*0.9^t
Step-by-step explanation:
At the beginning (t = 0) the sample has 600 grams. After 1 millennium from today (t = 1) the mass will be: 600 - 600*0.1 = 600*0.9. After 2 millennium from today (t = 2) the mass will be the 90% of the mass in the previous millenium, that is: 600*0.9*0.9 = 600*0.9^2. Analogously, at time = 3, sample's mass will be: 600*0.9^2*0.9 = 600*0.9^3. In a table format, that is
t m
0 600
1 600 - 600*0.1 = 600*0.9
2 600*0.9*0.9 = 600*0.9^2
3 600*0.9^2*0.9 = 600*0.9^3
Therefore, sample's mass in grams, S(t), where t refers to millennia from today is computed as follows: S(t) = 600*0.9^t
