Grades 1-2 Video Solutions 2023-2023_1-2

Video Transcription

Problem number nine. There are five trees in the park. A beaver can see only two of the trees because all the others are hidden behind other trees.  At which of the marked points is the beaver standing?  The idea behind this problem is that as the beaver is looking across the park, if there's a tree that's behind another tree from where he's looking,  and it's not any bigger than the first tree, he will not be able to see it.  So let's go through and figure out how many trees he would see from each of the points.  From A, he can look this way,  and he will see this tree,  and also this tree, because even though it's in the same line, it is bigger. He would also see this tree if he looks a little bit to his right, and he will see this tree.  So the beaver would see at least four trees from A.  From B, he looks this way, he will see at least this tree. This one might be hidden. He'll also see this one here. And looking this direction, he would see this tree.  And most likely, he would also see this one. So he will see at least four trees from B.  From C, looking in this direction, he sees this tree.  He can also see this one.  And he will see this one.  He might not be able to see this tree or this one, but he sees at least three trees.  From D, looking in this direction, the big tree hides these two. And then in this line, this big tree hides this one.  So from D, he sees two trees. Let's check E.  He could see this one.  Looking a little more to the left, this one.  Also this one.  He definitely sees this one, and he also most likely see this tree. So he might be able to see all five trees from E.  So it's only from point D that the beaver can see two trees. So the answer is D.

Video Summary

The problem involves determining the location from which a beaver in a park can see only two trees out of five, as others are obscured behind larger trees. Through analysis, from point A the beaver can see four trees, from point B four trees, from point C at least three trees, and from point E possibly all five trees. However, from point D, the beaver only sees two trees due to larger trees obstructing visibility. Thus, the beaver is standing at point D.