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27 votes
27 votes
Source A has a half-life of 10 million years, and source B has a half-life of 5 million years. After 10 million years, what percent of each source remains?

Group of answer choices

50% of source A and 0% of source B

25% of source A and 25% of source B

25% of source A and 0% of source B

50% of source A and 25% of source B

User Mark DeLoura
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2 Answers

18 votes
18 votes

Answer:

source A 50%

source B 25%

Step-by-step explanation:

Half life is time it takes for something to get reduced by half. For example, if half life of my weight is 5 years and I am currently 20lbs, then in next 5 years I will become half of my original so 10lbs.

Similarly, if compound A has half-life of 10 million years, then after 10 million years, half of compound A will remain, thus 50% remains

Compound b has half life of 5 million years, so first 5 million years it will reduce by half so become 50% but then in another 5 million years (total of 10 million years) it gets reduced by another half so 50/2 = 25% remains.

User Plumenator
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2.9k points
23 votes
23 votes

Answer:

50% of source A, and 25% of source B.

Step-by-step explanation:

You see, half-life of 10mil years means half of it will be gone in 10 million years. so basically, since source a is 10mil half life, half of it will remain, while source b, since it has 5 million years of half life, will have 25% left, since 1/2*1/2=1/4. hope this helps!

User Streamline
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2.6k points