In a new housing development, trees are to be planted along the sidewa

If you divide 166 by 15, you will have a remainder of 1.
So there is a space for 1 more tree since the length of each tree is 1 feet.
So total 12 trees.

I believe you are right Kunal555. My bad. Thanks for the correction. Kudos to you.

Hi All,

This is an example of a 'fence-post' problem, meaning that you have to account for the first 'post' (in this case, a tree), work down the line and account for the LAST 'post' (and there will ALWAYS be a last post, right at the very end).

We're told that a tree is 1 square-foot of space and that there is 14 feet of empty space between a tree and the next tree in line. Thus, each "tree-space" pair is 15 feet...

As we travel down the 166 foot row, we will have 166/15 = 11 remainder 1 "pairs." So there are the 11 trees that are part of each '15-foot pair' AND there's 1 foot of leftover space at the end - which is exactly enough room for 1 MORE TREE.

11+1 = 12

Final Answer:
GMAT assassins aren't born, they're made,
Rich

Step 1: Analyze the Question

Though this is not a Geometry question, a quick sketch of the situation will help illustrate how to solve it.



So we know that the unit of one tree and one space is 1 * 1 + 14 feet = 15 feet.

Step 2: State the Task

To find how many trees can be planted, determine the feet required for a tree and the space between trees. Divide the total length of the street by the unit of one tree and the space between trees.

Step 3: Approach Strategically

Each tree takes up 1 foot, and each space takes up 14 feet. Together they take up 15 feet. Now find how many times 15 goes into the total number of feet on one side of the street:

166/15= 11, with a remainder of 1 foot.

We can plant one last tree in the remaining foot, bringing the total number of trees to 12. This means along the street, we can plant 12 trees with 11 spaces between them, as long as we start and end with a tree. (E) is correct.

Step 4: Confirm Your Answer

Make sure your answer makes sense in the context of the question. Did you take into account the remainder of the division? Will an entire tree fit in the remaining space? You can use these questions to confirm your work.

Nice question. Might be helpful to people who don't like using algebra to sketch this out when trying to figure out how to solve it.

Trick is not to fall for the trap answer:

Start with planting a tree at the very front of the sidewalk:

1 ft

Then you will need to place 14 feet in between each tree

1 ft ————-1 ft ——— 1 ft——-
………..14…………….14……………14


So we can first see how many whole number intervals of 15 ft there are in 166 ft


15 * (11) = 165

So we can plant 11 trees with 14 feet intervals after each one

And then have 1 more foot left over. We can use this last 1 foot to plant 1 more tree.

11 + 1 =

12

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Whether it is not less than obvious from this statement that each tree would be taking 1 feet in length :

Each tree takes up one square foot of sidewalk space

Bunuel