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ss7ja [257]
3 years ago
13

Scientists found stone tool specimens in a cave in Africa. Using potassium–argon radiometric dating, they discovered that the to

ols contained 25 percent radioactive potassium-40. How old are the tools? (You must show your calculations to receive credit.) *The half-life for potassium-40 to argon-40 is 1.25 billion years.
Biology
1 answer:
juin [17]3 years ago
4 0
The potassium remaining is 1/4 of the original, so two half lives have passed.
One half life = 1.25 billion years
Two half lives = 1.25 x 2 = 2.5 billion years

The tools are 2.5 billion years old.
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