SOLUTION: Suppose that a sample of a radioactive substance having a half-life of 11,000 years was placed in a time capsule 1500 years ago. What percentage of the original sample remains toda

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Question 423293: Suppose that a sample of a radioactive substance having a half-life of 11,000 years was placed in a time capsule 1500 years ago. What percentage of the original sample remains today?


please...i really don't know how to solve it. could you explain in details????
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Suppose that a sample of a radioactive substance having a half-life of 11,000
years was placed in a time capsule 1500 years ago.
What percentage of the original sample remains today?
:
The half life formula:
A = Ao*2^(-t/h)
where
A = amt after t years
Ao = initial amt
t = time in yrs
h = half-life of the substance
:
In this problem:
let Ao = 100 (100%)
t = 1500 yrs
h = 11000
A = percent left after 1500 yrs
:
A = 100*2^(-1500/11000)
use a calc to find 2^(-1500/11000)
A = 100 * .90981
A = 90.98% left after 1500 yrs
:
did you understand what we did here? Any questions?