Algebra

posted by .

The level of thorium in a sample decreases by a factor of one-half every 2 million years. A meteorite is discovered to have only 8.6% of its original thorium remaining. How old is the meteorite?

  • Algebra -

    After 1 half life it will have 0.5 (or 1/2^1) remaining

    After 2 half lifes it will have 0.25 (or 1/2^2)remaining

    After 3 half lifes it will have 0.125 (or 1/2^3) remaining

    After n half lifes it will have 1/2^n remaining

    There is 0.086 remaining so

    0.086 = 1/2^n

    or 2^n=1/0.086

    solve for n to give you the number of half lives

    and n x 2 x 10^6 y = age of meteorite.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. algebra

    The level of thorium in a sample decreases by a factor of one-half every 4.2 million years. A meteorite is discovered to have only 7.6% of its original thorium remaining. How old is the meteorite?
  2. algebra

    2. The level of thorium in a sample decreases by a factor of one-half every 2 million years. A meteorite is discovered to have only 8.6% of its original thorium remaining. How old is the meteorite in millions of years?
  3. AP Calculus

    An Initial amount of 100 grams of Thorium-234 decays according to the model: dP/dt=-0.02828P (where t is measured in years). a) Find the equation for the amount of Thorium left after t years. b) Determine the half-life of this radioactive …
  4. math

    The mass m(t) remaining after t days from a 70 g sample of thorium-234 is given by the equation shown below. m(t) = 70e-0.0274t Find the half-life of thorium-234. (Round your answer to the nearest tenth.)
  5. chemistry

    how many more neutrons does thorium-230 have then protons?
  6. Physics

    A 27-pound meteorite struck a car in Peekskill, NY, creating a dent about 22 cm deep. If the initial speed of the meteorite was 550 m/s, what was the average force exerted on the meteorite by the car?
  7. science/math

    write and solve an algebraic equation to find the original mass of the sample of the radioactive isotope uranium -235, which has a half-life of 704 million years your sample is about 700 million years old and weighs 120 grams
  8. A.P. Chemistry

    Thorium-232 undergoes alpha decay and has a half-life of 1.4 * 10^10 years. How long will it take for a 1.00mg sample of thorium-232 to be reduced to 0.5mg?
  9. chemistry

    What would be the mass ratio of Pb-208/Th-232 in a meteorite that is approximately 4.5 × 10^9 years old?
  10. Science

    _____ is useful for dating very old rocks because it has a half-life of 1.3 billion years. A. thorium-232 B. potassium-40 C. uranium-235 D. carbon-14 is the answer D?

More Similar Questions