Answer
$\$472.26 \text{ billion}$
Work Step by Step
Since $2005$ is $35$ years after $1970,$ then $x=35.$ Substituting $x=35$ in the given equation, $
y=13.34x+5.36
,$ results to
\begin{array}{l}\require{cancel}
y=13.34(35)+5.36
\\
y=466.9+5.36
\\
y=472.26
.\end{array}
Hence, the approximate amound of restaurant sales in $2005$ is $
\$472.26 \text{ billion}
.$
