Radar and sonar can detect objects or people through walls, but they are too costly for consumer use. Researchers Fadel...
GMAT Craft and Structure : (Structure) Questions
Radar and sonar can detect objects or people through walls, but they are too costly for consumer use. Researchers Fadel Adib and Dina Katabi have shown, however, that there may be a comparatively _______ alternative: small changes to the Wi-Fi technology used in smartphones can give users a cheap way to count people or even identify their gestures through walls.
Which choice completes the text with the most logical and precise word or phrase?
infrequent
inexpensive
unmistakable
impractical
Step 1: Decode and Map the Passage
Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| "Radar and sonar can detect objects or people through walls, but they are too costly for consumer use." |
|
| "Researchers Fadel Adib and Dina Katabi have shown, however, that there may be a comparatively _______ alternative:" |
|
| "small changes to the Wi-Fi technology used in smartphones can give users a cheap way to count people or even identify their gestures through walls." |
|
Provide Passage Architecture and Core Elements
Main Point: Researchers have found that modified Wi-Fi technology could provide a cheaper alternative to expensive radar and sonar for detecting people through walls.
Argument Flow: The passage establishes a problem (radar and sonar are too expensive), introduces researchers who found a potential solution, then explains that Wi-Fi modifications can accomplish the same goals at lower cost.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- The blank comes after "comparatively," so we need a word that compares the Wi-Fi alternative to radar and sonar
- From our analysis, we know radar and sonar are "too costly for consumer use," while the Wi-Fi method gives users a "cheap way" to do the same thing
- The right answer should indicate that the Wi-Fi alternative is more affordable or less costly than radar and sonar
infrequent
✗ Incorrect
- "Infrequent" means rare or uncommon
- Does not create a logical comparison with the cost issue established
- The passage is not about how often these technologies are used
inexpensive
✓ Correct
- "Inexpensive" directly contrasts with "too costly"
- Creates the perfect comparison: radar/sonar are expensive, Wi-Fi alternative is inexpensive
- Reinforced by "cheap way" later in the sentence
unmistakable
✗ Incorrect
- "Unmistakable" means clear or obvious
- Does not relate to the cost comparison being established
impractical
✗ Incorrect
- "Impractical" means not feasible or workable
- Contradicts the entire premise that this is a viable alternative