Answer
213,500 board feet
Work Step by Step
First, find board feet of lumber contained in a single tree by dividing by the total number of trees. Then, find board feet of lumber in 2500 trees by multiplying the value obtained by 2500.
100 trees -->> 8540 board feet of lumber
$\div 100$
1 Tree -->> $\frac{8540}{100}$ board feet of lumber
$\times 2500$
2500 Trees -->> $\frac{8540}{100}\times 2500$ board feet of lumber
Total board feet of lumber expected to harvest=$\frac{8540}{100}\times 2500$
= 213,500
