Answer
Answer C
Work Step by Step
Given $S=858t^2+1412t+4982$
Instead of 50 million, we will set $S=50000$
Solve the equation: $858t^2+1412t+4982=50000\\
\Leftrightarrow 858t^2+1412t-45018=0\\
\Leftrightarrow t=\frac{-1412 \pm \sqrt 156495520}{1716}\\
\Leftrightarrow t\approx6.5 \land t=-8.1$
Since $t$ cannot be negative, we will ignore the negative solutions.
For $t$ is a number of years since $1990$, $y=6.5$. This means the answer is $1996$.
Answer C.
