The half life of a certain radioactive material is 36 days.

The half life of a certain radioactive material is 36 days. An initial amount of the material has a mass of 487 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 5 days. Round your answer to the nearest thousandth.

a)y=487(1/2)^36x ; 0.318kg

b)y=2(1/487)^1/36x ; 0.847kg

c)y=487(1/2)^1/36x ; 442.302kg

d)y=2(1/487)^36x ; 0kg

2 Answers

  • A = A(o)[0.5^(t/t(1/2)]

    A = 487[0.5^5/36] = 487(0.9082) = 442.302kg

    • .--
  • c)

y = 487 * (1/2)^(x/36); 442.302

All the others have too little stuff left when only 5 days has past and you need 36 days to get to 1/2 of the stuff.

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