Answer:
A(10) = 400
Step-by-step explanation:
[tex]A(t) = t^{2} + 300[/tex]
Plug in 10 to the equation to get A(10)
[tex]A(10) = (10)^{2} + 300[/tex]
[tex]A(10) = 100 + 300 = 400[/tex]