### GMATPrep Problem Solving: Kaye’s Stamps

Some people really like ratio problems while others struggle with these. What do you think?

Let’s talk about a go-to solution method when handling a problem of this type. Try this GMATPrep problem:

* ” The number of stamps that Kaye and Alberto had were in the ratio 5 : 3, respectively. After Kaye gave Alberto 10 of her stamps, the ratio of the number Kaye had to the number Alberto had was 7 : 5. As a result of this gift, Kaye had how many more stamps than Alberto?

“(A) 20

“(B) 30

“(C) 40

“(D) 60

“(E) 90”

My very first thought as I read this problem: I have to be very careful with my work here, because it would be really easy to solve for the wrong thing (and, of course, that wrong answer will probably be among the answer choices).

As an aside, I’ve found that this attitude is one of the biggest differences between someone who has the potential to hit a top score on quant and someone who won’t make it. When you see something and you think, “I know how to do this!” the top test-taker is going to go in The Zone and pay even more attention to detail, thinking “I am going to be really careful not to make a mistake on this one!” Someone who isn’t going to hit a tip-top score will instead start to coast a little mentally, thinking, “Yeah, I’ve already got this.” Even worse, someone might think, “I can speed up on this one since I know how to do it.”

No! Don’t speed up! You don’t necessarily have to take the full 2 minutes, but don’t go any faster than you’d normally go. Don’t increase the chances that you make a careless mistake!

Okay, let’s solve this thing.

First, make very clear on your scrap paper what you want: Kaye NEW minus Alberto NEW. Not just Kaye (new or old). Not Kaye’s original number of stamps minus Alberto’s original number.

Skip a few lines and write this on the scrap paper and put a big circle around it: K_{n }– A_{n}. Do the actual work up above this text and, when you’re done, you’ll “run into” the reminder that you want Kaye NEW minus Alberto NEW.

Also, make sure you organize your work carefully as you go so that you know which portions represent the original numbers versus the new ones.

Let’s see.

### GMAT Challenge Problem Showdown: July 29, 2013

We invite you to test your GMAT knowledge for a chance to win! Each week, we will post a new Challenge Problem for you to attempt. If you submit the correct answer, you will be entered into that week’s drawing for a free Manhattan GMAT Prep item. Tell your friends to get out their scrap paper and start solving!

Here is this week’s problem:

A total of

mdifferent points are selected on a particular line, and a total ofndifferent points are selected on another line parallel to the first, where each ofmandnis greater than 1. In how many different ways can a triangle be made with its vertices at three of the selected points?A.

m^{2}n+mn^{2}B.

mn(m+n– 2)C.

D.

E.

### Free GMAT Events This Week: July 29 – August 4

Here are the free GMAT events we’re holding this week. All times are local unless otherwise specified.

**7/29/13**– Philadelphia, PA – Free Trial Class– 6:30PM- 9:30PM

**7/30/13**– San Francisco, CA- Free Trial Class– 6:30PM- 9:30PM

**7/30/13**– Online- Free Trial Class– 8:00PM- 11:00PM (EDT)

**7/30/13**– New York, NY- Free Trial Class– 6:30PM- 9:30PM

**7/30/13**– Washington, DC- Essay Writing Workshop presented by mbaMission– 7:00PM- 8:30PM

**7/31/13**– London – Free Trial Class– 6:30PM- 9:30PM

**7/31/13**– Chicago, IL- Free Trial Class– 6:30PM- 9:30PM

**7/31/13**– New York, NY-Essay Writing Workshop presented by mbaMission– 7:00PM- 8:30PM

**8/1/13**– Chicago, IL- Assessing Your MBA Profile presented by mbaMission– 7:00PM- 8:30PM

**8/3/13**– Online- Free Trial Class– 1:00PM- 4:00PM (EDT)

**8/4/13**– Online- Free Trial Class– 10:30AM- 1:30PM (EDT)

**8/4/13**– Santa Monica, CA – Free Trial Class– 2:00PM- 5:00PM

Read more

### Manhattan Prep Giving Back

It’s been a very busy 2013 here at Manhattan Prep! We’ve already worked with over a dozen non-profit organizations this year, supporting their programming and initiatives through in-kind donations, discount programs, and much more. We love to find new ways to team up with these organizations, connecting with pre-MBAs from all over the country who are striving to make a difference.

Below are some highlights from our giving so far this year. We encourage you to check out these organizations to see what awesome things they’ve been up to!

### Friday Links: Startups, Accredited MBAs, TED Talks, & More!

Catch up on some business school news and tips with a few of this week’s top stories:

Startups Recruiting More MBAs (*Poets & Quants*)

Startups are getting increased attention from MBAs and they’re apparently returning the love, according to a new survey.

Why Your MBA Should be Accredited (*About.com Education*)

If the degree or business school is not accredited, your achievements may not even be recognized by an employer.

14 of the Most Essential Lessons You Learn in Business School (*Business Insider Australia*)

Top business professors share which case studies they think are the most essential for future business leaders.

The Best TED Talks By B-School Professors (*Poets & Quants*)

Generally, the best TED talks by B-school faculty tend to be delivered by professors whose names are rarely mentioned outside their own schools.

Master the MBA Interview as an International Candidate (*U.S. News Education*)

Prospective students should anticipate making some mistakes when speaking English, but shouldn’t expect that to ruin the interview.

Did we miss your favorite article from the week? Let us know what you have been reading in the comments below or tweet @ManhattanGMAT

### GMAT Challenge Problem Showdown: July 22, 2013

We invite you to test your GMAT knowledge for a chance to win! Each week, we will post a new Challenge Problem for you to attempt. If you submit the correct answer, you will be entered into that week’s drawing for a free Manhattan GMAT Prep item. Tell your friends to get out their scrap paper and start solving!

Here is this week’s problem:

In the

xy-coordinate plane, lineLpasses through the points (b,a) and (c, 0), and lineMpasses through the point (a,b) and the origin, wherea,b, andcare different nonzero integers. Do linesLandMintersect?(1)

(2)

c< 0

### GMAT Percentiles Update

Last week, GMAC updated its percentiles for GMAT scores. The organization does this once a year to smooth out any differences in the testing pool.

What do I mean by “differences?” The demographics of the people taking the exam change over time. In particular, over the last ten years or so, GMAC has seen a huge increase in the number of non-United-States-based students taking the test. A majority of these students speak English as a second (or third!) language; a majority also have a better grounding in quantitative skills than the average U.S.-educated student. These differences lead to changes in the data over time.

### Scaled Scores vs. Percentiles

GMAT results are reported using various “scaled scores.” We receive a 2-digit score for quant, a separate 2-digit score for verbal, a Q+V-combined 3-digit score, and two more separate scores for the essay and IR sections.

Think of these scaled scores as “skill levels.” They reflect a specific, measurable level of ability. Here’s the interesting thing: the skills needed to reach a certain level do not change over time. A quant score of 45 today reflects the *same* skill level as a quant score of 45 earned ten or even twenty years ago.

What does change over time is the percentile ranking associated with that score. A percentile ranking reflects how much better you did than a certain percentage of the test-taking population. For example, if you score in the 75^{th} percentile, then you scored better than 75% of the people taking the test—not just that day, or that week, but for the past couple of years (or whatever timeframe is designated for that test).

Imagine that you give a math test to a bunch of 10-year-olds. The scoring algorithm is very simple: if you get a question right, you get one point. You then gather all of the scores and figure out percentile rankings for that group. Let’s say that a certain score (let’s call it 5) represents the 50^{th} percentile. A student who scores 5 earned a better score than 50% of her peers.

Then you take that exact test and give it to a bunch of 14-year-olds. They’re a lot better at math. The same score of 5 might represent only the 25^{th} percentile for this new group, because more of these students have better math skills and can answer more questions correctly. A score of 5 still means the same thing (in this case, 5 questions right), but the pool of testers has changed and so the percentile rankings change too.

This is essentially what happens with the GMAT over time as well. If more people who are good at math start taking the test, then that score of 45 (which represents a certain, fixed level of skill) will drop in the percentile rankings because more people will be capable of performing at that level or higher.

We’ve seen especially big demographic changes on the GMAT over the last 5 to 10 years. In 2006, a quant score of 45 was rated the 78^{th} percentile. Someone scoring at that level had better quant skills than 78% of the people taking the exam around that time.

Today, that *same* skill level of 45 rates the 66^{th} percentile. This does *not* mean that someone scoring a 45 today is worse at math than someone with the same score in 2006; rather, the two students are equally good. Instead, a greater percentage of the *population taking the test today* has stronger math skills.

You might be thinking: oh, great. So that means I have to do even better at math. Actually, the opposite is (sort of) true. Keep reading.

### This Year’s Trends

### The Second Level of Learning to Take the GMAT

You already know how to learn—you’ve been learning all your life. The problem is that the way you learn best for school is often not the best way of learning to take the GMAT. Read more

### Free GMAT Events This Week: July 22 – July 28

Here are the free GMAT events we’re holding this week. All times are local unless otherwise specified.

**7/22/13**– Chicago, IL – Free Trial Class– 6:30PM- 9:30PM

**7/22/13**– Boston, MA- Assessing Your MBA Profile presented by mbaMission– 7:00PM- 8:30PM

**7/22/13**– Austin, TX- Free Trial Class– 6:30PM- 9:30PM

**7/23/13**– Online – Live Online GMAT Preview– 8:00PM- 9:30PM (EDT)

**7/23/13**– New York, NY – Writing a Standout HBS Application Essay presented by mbaMission– 7:00PM- 8:30PM

**7/24/13**– Santa Monica, CA – Free Trial Class– 6:30PM- 9:30PM

**7/24/13**– Toronto, ON- Free Trial Class– 6:30PM- 9:30PM

**7/25/13**– Online – Free Trial Class– 9:00PM- 12:00PM (EDT)

**7/25/13**– Boston, MA- Free Trial Class– 6:30PM- 9:30PM

Read more

### Friday Links: Wharton’s GMAT Record, Leadership Lessons, &More!

Catch up on some business school news and tips with a few of this week’s top stories:

Wharton’s Record GMATs for New Class (Poets and Quants)

Despite a 5.8% fall in MBA applications, Wharton said it has enrolled a larger first-year class of 855 with an average GMAT score that is seven points higher at 725.

The World’s Best Business Schools (Business Insider)

Having an MBA can give you an edge in the cutthroat world of business—but only if you pick the right school.

Leadership Lessons from The Harvard of Europe (Forbes)

Associate Dean at HEC Paris talks about how leadership is far more about being knowledgeable and gaining respect than being able to do a good presentation in the boardroom.

Cornell To Offer One-Year MBA in NYC (Poets and Quants)

The Johnson Graduate School of Management at Cornell University will soon offer a one-year MBA program based at Google’s New York City campus.

MBA Teaching urged to move away from focus on shareholder primacy model (Financial Times)

Academics and others are being increasingly vocal about how deeply entrenched the idea of shareholder primacy is in management.

Did we miss your favorite article from the week? Let us know what you have been reading in the comments below or tweet @ManhattanGMAT