ANSWER
c). Two and half years (2.5 years).
EXPLANATION
Given:
[tex]A\text{ = }\frac{276}{1\text{ + 11}e^{-0.35t}}[/tex]Desired Outcome:
The number of years it will take for the herd to grow to 50 deer
Determine time 't'
[tex]\begin{gathered} 50\text{ = }\frac{276}{1\text{ + 11}e^{-0.35t}} \\ 50(1\text{ + 11}e^{-0.35t})\text{ = 276} \\ 50\text{ + 550}e^{-0.35t}\text{ = 276} \\ 550e^{-0.35t}\text{ = 276 - 50} \\ e^{-0.35t\text{ }}\text{ = }\frac{226}{550} \\ e^{-0.35t}\text{ = 0.4109} \\ \ln e^{-0.35t}\text{ = }\ln(0.4109) \\ -0.35t\text{ = -0.8894} \\ t\text{ = }\frac{-0.8894}{-0.35} \\ t\text{ = 2.5 } \\ t\text{ = 2}\frac{1}{2}\text{ years} \end{gathered}[/tex]Hence, it will take two and half (2.5) years for the herd to grow to 50 deer.