Radioactive substance has a half life of 18 years. Decay rate remains constant how long will it before 95 percent of the sample has decayed?
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Hello, av8or91!
The half-life function is: .A radioactive substance has a half life of 18 years. Decay rate remains constant.
How long will it be before 95 percent of the sample has decayed?
. . where is the intial amount and .
Our function is: .
If 95% of the sample has decayed, then: .
We have: .
Take logs: .
. .