Respuesta :
Answer: (263.1 years) x (half-life / 87.7 years) = 3 half-lifes In 3 half-lifes, (1/2 x 1/2 x 1/2) = 1/8 of the atoms in a sample remain unchanged. That's 12.5% that remain unchanged. The other 87.5% of the atoms in the sample have decayed, and changed to either other isotopes of plutonium or into atoms of other elements.
Answer: The first one is ⇒ 12.5%
The second one is ⇒ 87.5%
I would appreciate brainliest :)