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Radioactive elements decay at a know rate known as half-life. Choose all of the correct statements concerning half-life.

Carbon-14 has a half-life of 5,730 years. A 30 gram sample will be 10 grams after 5,730 years.
Nickel-59 has a half-life of 76,000 years. A sample would go through 3 half-lives in 228,000 years.
Hafnium-182 has a half-life of 9 million years. A 38 gram sample would be 4.75 grams in 27 million years.
Iron-60 has a half-life of 1.5 million years. In 6 million years a 40 gram sample would be reduced to 10 grams.
Lead-202 has a half-life of 52,500 years. The original sample must have been 120 grams if you have a 60 gram sample after 105,000 years.