9514 1404 393
Answer:
16 mg
Step-by-step explanation:
The decay of the sample can be modeled by ...
y = a·b^t
where y is the mass of the sample t years after 1990.
We are given that ...
440 = a·b^0 ⇒ a = 440
40 = 440·b^8 ⇒ b = (40/440)^(1/8) ≈ 0.741013
Then in 2001, t=11 and the mass is modeled to be ...
y = 440·0.741013^11 ≈ 16.3 . . . mg
The expected mass in the year 2001 is 16 mg.
