In 2007, computer scientist Luis von Ahn was working on converting printed books into a digital format. He found that...
GMAT Craft and Structure : (Structure) Questions
In 2007, computer scientist Luis von Ahn was working on converting printed books into a digital format. He found that some words were distorted enough that digital scanners couldn't recognize them, but most humans could easily read them. Based on that finding, von Ahn invented a simple security test to keep automated 'bots' out of websites. The first version of the reCAPTCHA test asked users to type one known word and one of the many words scanners couldn't recognize. Correct answers proved the users were humans and added data to the book-digitizing project.
Which choice best states the main purpose of the text?
To discuss von Ahn's invention of reCAPTCHA
To explain how digital scanners work
To call attention to von Ahn's book-digitizing project
To indicate how popular reCAPTCHA is
Step 1: Decode and Map the Passage
Part A: Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'In 2007, computer scientist Luis von Ahn was working on converting printed books into a digital format.' |
|
| 'He found that some words were distorted enough that digital scanners couldn't recognize them, but most humans could easily read them.' |
|
| 'Based on that finding, von Ahn invented a simple security test to keep automated 'bots' out of websites.' |
|
| 'The first version of the reCAPTCHA test asked users to type one known word and one of the many words scanners couldn't recognize.' |
|
| 'Correct answers proved the users were humans and added data to the book-digitizing project.' |
|
Part B: Passage Architecture & Core Elements
Main Point: Luis von Ahn invented reCAPTCHA as a security test that cleverly solved two problems at once—keeping bots out of websites while helping digitize books.
Argument Flow: The passage follows a clear problem-solution structure. It starts with von Ahn's digitization work, identifies the specific challenge he encountered with distorted text, then explains how he turned this challenge into an innovative security solution that served dual purposes.
Step 2: Interpret the Question Precisely
What's being asked? The main purpose of the entire text
What type of answer do we need? The primary reason this passage was written—what the author's main goal was in presenting this information
Any limiting keywords? 'main purpose' tells us to focus on the central objective, not subsidiary details
Step 3: Prethink the Answer
- The passage clearly follows von Ahn's journey from digitization work to invention
- The central focus is on how he created reCAPTCHA—the problem that led to it, what it does, and why it's clever
- While the book digitization project is mentioned, it serves as background context for the invention story
- The technical details about scanners and the dual benefits all support the main narrative about the invention itself
To discuss von Ahn's invention of reCAPTCHA
- Correct - Matches our analysis perfectly—the passage is structured around telling the story of von Ahn's invention
- Covers the main narrative arc from problem discovery to solution creation
- All other details in the passage support this central story
To explain how digital scanners work
- Incorrect - The passage mentions how scanners work, but only as context for understanding the invention
- Scanner functionality isn't the main focus—it's just the problem that inspired the solution
To call attention to von Ahn's book-digitizing project
- Incorrect - The book-digitizing project is the starting point, not the main purpose
- The passage uses digitization as context to explain how reCAPTCHA came about
To indicate how popular reCAPTCHA is
- Incorrect - The passage never discusses reCAPTCHA's popularity or widespread adoption
- Focuses on the invention and how it works, not its success or usage statistics