Pre Calculus

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Exponential growth and decay


find the half life of a radioactive substance if 220 grams of the substance decays to 200 grams in 4 years?

  • Pre Calculus -

    Let the half life be T years

    2^(-4/T) = 200/220 = 0.9091
    (-4/T) log 2 = log 0.9091
    -4/T = -0.1375
    T = 29.1 years

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