$[1/2$ Points$]$ HARMATHAP$1013\mathrm{.}3\mathrm{.}041.$

With data from the Social Security Trustees Report for selected years from $1950$ and projected to $2030,$ the number of Social Security beneficiaries $($in millions$)$ can be modeled by

$B(t)=0\mathrm{.}00024t^3-0\mathrm{.}026t^{2}1\mathrm{.}6t2\mathrm{.}2$

where $t$ is the number of years past $1950.$ Use the model to find the average number of Social Security beneficiaries per year $($actual and predicted$)$ between the following. $($Round your answers to three decimal places.$)$

$($a$)1983$ and $2008$

X million per year

$($b$)1990$ and $2022$

$q,$ million per year