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After the first half-life, then ½ (5.12 × 1020) = 2.56 × 1020 will have decayed.
The second half-life, then ½ (2.56 × 1020) = 1.28 × 1020 will have decayed.
The total number of decayed atoms = (2.56 + 1.28) × 1020 = 3.84 × 1020 atoms.
Mutiso answered the question on October 17, 2018 at 10:10
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