GMAT OFFICIAL GUIDE DS

Solution:

We are given a diagram of an L-shaped garden. Let’s sketch that diagram below.

The figure above represents an L-shaped garden...

We see that the L-shaped garden can be broken up into smaller shapes. Let’s sketch that below.

Statement One Alone:

The area of the garden is 189 square feet.

Using our diagram of smaller shapes and the information from statement one we can create the following equation:

(15)(k) + (15 – k)(k) + = 189

15k + 15k – k^2 = 189

k^2 – 30k + 189 = 0

(k – 9)(k – 21) = 0

k = 9 or k = 21

Referencing our diagram we see that k cannot be 21; thus, k must be 9. Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C, and E.

Statement Two Alone:

The perimeter of the garden is 60 feet.

Using our diagram of smaller shapes and the information from statement two we can create the following equation:

k + (15 – k) + k + 15 + k + (15 – k) + (15 – k) = 60

60 = 60

Notice that all the occurrences of k canceled out. Thus, we cannot determine a value for k. Statement two alone is not sufficient to answer the question.

Answer: A

About The Author

Scott Woodbury-Stewart is the founder & CEO of Target Test Prep. A passionate teacher who is deeply invested in the success of his students, Scott began his career teaching physics, chemistry, math, and biology. Since then, he has spent more than a decade helping students gain entry into the world’s top business schools, logging 10,000+ hours of GMAT, EA, GRE and SAT instruction. Scott also served as lead content developer and curriculum architect for the revolutionary courses Target Test Prep GMAT, Target Test Prep EA, Target Test Prep GRE and Target Test Prep SAT Quant.