Given:
The function models the number of movie theaters in the United States t years after 1985.

To find:
The year in which the United States will have 35,000 movie theaters.
Solution:
We have,

Putting f(t)=35000, we get



Divide both sides by 750.


It means, United States will have 35,000 movie theaters 20 years after 1985.

Therefore, United States will have 35,000 movie theaters is 2005.