Answer:
There will be 333 elm trees in the area.
Step-by-step explanation:
10 km x 10 km = 100 km²
1 km x 1 km = 1 km²
Since the scientists divided the area into 1 km² quadrants and counted the trees in them, we need to see how many of these quadrants there are in the whole area, which can simply be done by dividing the whole area by the size of the smaller quadrants:
100 / 1 = 100
Having found out that we have 100 smaller quadrants, next we need to find out an average of how many trees there are in the three randomly selected quadrants, and then apply that average for all of them:
(5 + 3 + 2) / 3 = 3.33
3.33 x 100 = 333
We got 3.33 elm trees on average per small quadrant and applying that number to all 100 quadrants we got a number of 333 elm trees in all of the area.