Answer
$2.258$
Work Step by Step
We need to use an exponential decay model such as:
$y= q( \dfrac{1}{2})^{t/5715}$
or, $q=\dfrac{y}{( \dfrac{1}{2})^{t/5715}} $
or, $q= y \times ( \dfrac{1}{2})^{-t/5715}$
The amount after $1000$ years is:
$q= 2 \times ( \dfrac{1}{2})^{-1000/5715} \approx 2.258$
