Engineering Board Exam Reviewer · Applications: Growth and Decay · easy
A radioactive substance has a half-life of 10 days. What percent of the original amount remains after 25 days?
- 25%
- 12.5%
- 35.36%
- 17.68%
Answer
D. 17.68%
Solution
A=A0≤ft( 12 )t/10. At t=25: A/A0=≤ft( 12 )2.5 0.1768, which is about 17.68%.
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