Simplification

[Joy Shaha]

Q. In a garden there are 10 rows and 12 columns of trees.The distance between any two trees is 2 m and a distance of 1 m is left from all sides of the boundary of the garden.What is the length of the garden?
A.20 B.22, C.24, D.26

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Hi Joy Shaha,

What is the source of this question? I ask because it's poorly worded and does not match the 'style' of the questions that you'll see on the Official GMAT. This question also appears to ignore the length/width of each tree (which would impact the length and width of the garden). If you're actually studying for the GMAT, then you might want to invest in more reputable practice materials.

Its 'intent' is to have you count the 'space' between each pair of trees. Since the length of the garden is 12 trees, there are 11 two-meter 'spaces' between those 12 trees. When you add the extra 1 meter on either end, you end up with 11(2) + 1 + 1 = 24 meters.

Final Answer: C

GMAT assassins aren't born, they're made,
Rich

[Brent@GMATPrepNow]

To add to Rich's great critique of this not-so-great question, the question seems to assume that a garden is a rectangle, when it's also possible to adhere to the given conditions by having corners that are rounded.

If you're interested, here's an article on identifying GMAT-worthy questions: https://www.gmatprepnow.com/articles/questions-questions

Cheers,
Brent

[Matt@VeritasPrep]

This is probably from India's CAT. Questions from that test tend to have four answers and be poorly worded, but also to demand more sophisticated reasoning than GMAT questions do. Even by the standards of some of the most poorly worded questions from that test, however, this one is awful! (How can the distance between two trees four columns away be 2, while the distance between two threes three columns away is also 2? Fire the author!)

Anyway, let's consider the problem. I think the author must mean that the distance between any two ADJACENT trees in the same row is 2, and the distance between any two ADJACENT trees in the same column is 2.

Given that, we have 12 columns, so there are 11 two-meter distances between them, or 11*2. We also have a one-meter distance at each end of the garden, or 1*2. Summing up, we've got 11*2 + 1*2, or 24.

[Matt@VeritasPrep]

This is probably from India's CAT. Questions from that test tend to have four answers and be poorly worded, but also to demand more sophisticated reasoning than GMAT questions do. Even by the standards of some of the most poorly worded questions from that test, however, this one is awful! (How can the distance between two trees four columns away be 2, while the distance between two threes three columns away is also 2? The author is asleep at the wheel, big time.)

Anyway, let's consider the problem. I think the author must mean that the distance between any two ADJACENT trees in the same row is 2, and the distance between any two ADJACENT trees in the same column is 2.

Given that, we have 12 columns, so there are 11 two-meter distances between them, or 11*2. We also have a one-meter distance at each end of the garden, or 1*2. Summing up, we've got 11*2 + 1*2, or 24.