The total annual revenue (in billions of dollars) for the Boeing Corporation from 1990 to 2002 is given by
$\displaystyle {R}{\left({t}\right)}=-{0.1}{\left({t}-{3}\right)}^{{2}}+{80}$
where $\displaystyle {t}={0}$ is January 1, 1990. The annual revenue (also in billions of dollars) that Boeing made just from sales of its 737 airplane in the same period is given by
$\displaystyle {A}{\left({t}\right)}={0.2}{\left({t}-{8}\right)}^{{2}}+{30}$

In what year and month was annual revenue excluding sales of 737s at a maximum
Select an answer September November December August February January April October March July May June

What was that maximum revenue (in billion dollars per year)?
(nearest 0.1 billion dollars per year)