Bookshelf
Total GMAT Math Jeff's complete Quant guide, on sale now! |
Total GMAT Verbal Everything you need to ace GMAT Verbal! |
New: GMAT 111 Improve every aspect of your GMAT prep! |
1,800 Practice Math Questions
GMAT Official Guide
OG Math | OG Verbal
Guides To the Official Guide
Free: OG12 explanations!
GMAT Question of the Day
Beginner's Guide to the GMAT
GMAT Hacks Affiliate Program
Categories
- General Study Tips
- Goals and Planning
- CAT Strategy
- The Mental Game
- GMAT Math Strategy
- GMAT Math Topics
- Mental Math
- Data Sufficiency
- Critical Reasoning
- Reading Comprehension
- Sentence Correction
- Analytical Writing Assessment
- Business School Admissions
- GMAT Prep Resources
- Practice Questions
- Total GMAT Math
- Total GMAT Verbal
Official Guide Explanation:
Data Sufficiency #25
Background
This is just one of hundreds of free explanations I've created to the quantitative questions in The Official Guide for GMAT Review (12th ed.). Click the links on the question number, difficulty level, and categories to find explanations for other problems.
These are the same explanations that are featured in my "Guides to the Official Guide" PDF booklets. However, because of the limitations of HTML and cross-browser compatibility, some mathematical concepts, such as fractions and roots, do not display as clearly online.
Click here for an example of the PDF booklets. Click here to purchase a PDF copy.
Solution and Metadata
Question: 25
Page: 274
Difficulty: 5 (Moderate)
Category 1: Word Problems > Rate Problems > other
Explanation: Call Carmen's current weekly pay p, which is given as follows:
p = 30x, where x is her hourly rate.
If her hourly rate were increased by $1.50, it would be (x + 1.5). Her new number of hours is h in the following equation:
p = h(x + 1.5)
Note that p remains the same -- the question asks us how many fewer hours she'd need to work to maintain the same weekly pay. The value of figuring out the algebraic representation is that we know how many variables we're working with. We have three variables (p, x, and h), and two equations. If we can get one more equation without adding any new variables, we can answer the question.
Statement (1) is sufficient. If p = 225, we have our third equation. To solve, you can plug p = 225 into the first equation to find x, then plug p and x into the second equation to find h.
Statement (2) is also sufficient. If 1.50 is 20% of her current hourly wage, 1.5 = 0.2x. Again, it's a third equation with no new variables. We can plug in the resulting value of x into the first equation and use the results to find h in the second equation. Choice (D) is correct.
Click here for the full list of GMAT OG12 explanations.
You should follow me on Twitter. While you're at it, take a moment to subscribe to GMAT Hacks via RSS or Email. |
Total GMAT Math
The comprehensive guide to the GMAT Quant section. It's "far and away the best study material
available," including over 300 realistic practice questions and more than 500 exercises! |