Answer:
It will take 15 days for the same crew to clear the entire plot of 2 1/2 acres.
Explanation:
Given that a crew clears brush from 1/3 acre of land in 2 days, to determine how long will it take the same crew to clear the entire plot of 2 1/2 acres, the following calculation must be performed: 
 
1/3 = 0.333 
1/2 = 0.5 
 
0.333 = 2 
2.5 = X 
2.5 x 2 / 0.333 = X 
15 = X 
 
Therefore, it will take 15 days for the same crew to clear the entire plot of 2 1/2 acres.