Answer
$3.72\times10^{-3} g$ of lead
Work Step by Step
$10^6$g of blood contains $0.62 g$ of lead
$6\times10^3$g of blood contains $x$ g of lead
$\frac{0.62}{10^6}=\frac{x}{6\times10^3}$
$x=\frac{(6\times10^3)(0.62)}{10^6}$
$=3.72\times10^{-3} g$ of lead
