A laboratory investigation shows that a sample of uranium ore contains
7.22mg
of
_(92)^(283)U
(molar mass
238.05079(g)/(m)ol
) and
1.65mg
of
_(82)^(206)Pb
(molar mass
{:205.97447(g)/(m)ol)
. Calculate the age of the ore. The halifife of
_(92)8U
is
4.5\times 10^(9)yr
.