There isn't enough info to determine that, I believe. You would need an equation that would allow me to determine the minimum output for an A.
You can set up a proportion to determine the length of the enlarged photo
R equals approximately 4/5
Given:
Total forest area = 43,000
Old growth trees forest = 0.2%
To find:
The area of the old growth trees.
Solution:
We have,
Total forest area = 43,000
Old growth trees forest = 0.2%
Area of the old growth trees = 0.2% of 43,000
= 
= 
Therefore, the area of the old growth trees is 86 acres.