# A ratio isotope has a half life 10 days. If today there is 125 g of it left, what was its weight 40 days earlier?

$\begin {array} {1 1} (a)\;600\;g & \quad (b)\;1000\;g \\ (c)\;1250\;g & \quad (d)\;2000\;g \end {array}$

(d) 2000 g
answered Nov 7, 2013 by