Question 1143674
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An equation of the radioactive decay in this case is 


    {{{C*(1/2)^(t/5600)}}} = {{{0.76*C}}},


where C is the initial mass of carbon-14 in the sample; t is the time in years.


Simplify and solve for "t", which is the major unknown in this case.

Start canceling "C" in both sides.


    {{{(1/2)^(t/5600)}}} = 0.76


Take logarithm base 2 from both sides


    -t/5600 = {{{log(2,0.76)}}}


    -t/5600 = -0.39593


    t = 5600*0.39593 = 2217 years.      <U>ANSWER</U>
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