A scientist found an unweathered igneous rock that contained 0.025 g of potassium-40 and 0.075 g of argon-40. The half-life of potassium-40 is 1.3 billion years. Using the table from Figure 26.3 the age of the rock would be estimated to be
A. 1.3 billion years old.
B. 2.6 billion years old.
C. 0.050 billion years old.
D. 0.001875 billion years old.
E. 1.69 billion years old.
Answer: B
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