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  • one year ago

A rock has 50 percent of its original amount of potassium-40 remaining in it. Potassium-40 has a half-life of 1.25 billion years. How long ago was the rock formed? 1.25 billion years ago 2.50 billion years ago 5.00 billion years ago 6.25 billion years ago

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  1. anonymous
    • one year ago
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    Half-Life Definition: The time required to convert one half of a reactant to product. The term is commonly applied to radioactive decay, where the reactant is the parent isotope and the product is a daughter isotope. The answer is in the same question, is like asking "what color is Peter's white horse?"

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