5. Strontium-90 has a half life of 28.8 years. If you start with a 10 gram sample of Strontium-90, how much willI be left after 115.2 years?

Xavier is at NASA analyzing Moon rocks. In one of the rocks from the lunar maria, he discovered 79 % of the original uranium-238 remains, while remaining amount of uranium-238 had decayed into lead. The half life of uranium-238 is 4.5 × 109 years. Assume the only decay product is lead. How old is the lunar maria rock in billions of years (109 years)?

The half-life of radioactive strontium-90 is 28.8 years. How long would it take when only 16.5% of the original strontium-90 sample remains?

The half-life of nickel-63 is 100.1 years. If there are 100 grams of nickel-63 present at a certain time, how grams of nickel-63 will remain in 400.4 years? 50.0 12.5 6.25 25.0 It will all be gone