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

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
Similar Questions

algebra
The level of thorium in a sample decreases by a factor of onehalf every 4.2 million years. A meteorite is discovered to have only 7.6% of its original thorium remaining. How old is the meteorite? 
algebra
2. The level of thorium in a sample decreases by a factor of onehalf 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? 
AP Calculus
An Initial amount of 100 grams of Thorium234 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 halflife of this radioactive … 
math
The mass m(t) remaining after t days from a 70 g sample of thorium234 is given by the equation shown below. m(t) = 70e0.0274t Find the halflife of thorium234. (Round your answer to the nearest tenth.) 
chemistry
how many more neutrons does thorium230 have then protons? 
Physics
A 27pound 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? 
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 halflife of 704 million years your sample is about 700 million years old and weighs 120 grams 
A.P. Chemistry
Thorium232 undergoes alpha decay and has a halflife of 1.4 * 10^10 years. How long will it take for a 1.00mg sample of thorium232 to be reduced to 0.5mg? 
chemistry
What would be the mass ratio of Pb208/Th232 in a meteorite that is approximately 4.5 × 10^9 years old? 
Science
_____ is useful for dating very old rocks because it has a halflife of 1.3 billion years. A. thorium232 B. potassium40 C. uranium235 D. carbon14 is the answer D?