### The Math Beast Challenge Problem of the Week – Apr 29, 2013

If and are positive integers, what is the least possible value of

xy?

### Friday Links: Sleep in Grad School, Tips for Productivity, and More!

It’s that time of the week to catch up on some of the top grad school tips and news links from the week. Happy reading!

Sleep in Graduate School: Why Depriving Yourself of Sleep is a Terrible Idea (Grad Hacker)

Cutting back on sleep is never a good solution to getting your work done. In fact the opposite is true: healthy, sound sleep can be your key to success in graduate school.

Overwhelmed with End-of-the Semester Tasks? (About.com Graduate Schol

Whether you’re already in grad school or finishing up the Spring Semester in college, these final weeks can be very overwhelming. Here are some tips to ease the stress.

The Impossible Decision (The New Yorker)

Now that it’s springtime, college students who received acceptance letters to graduate school need to answer the complicated, inevitable question: To go, or not to go?

12 Tips For Increasing Productivity (Forbes)

Forbes has some good news”productivity is something that can be continuously improved. Here are some great pointers to help you focus your efforts and plan intelligently.

Did we miss your favorite article from the week? Let us know what you’ve been reading in the comments or tweet @ManhattanPrep

### Exercise Makes You Smarter

I just read a really fascinating post on the New York Times’ Well blog. We’ve known for a long time that exercise has a whole host of good benefits, including benefits associated with memory. Two recent studies have delved even deeper into how this works.

### How does exercise help memory?

In the blog post, New York Times journalist Gretchen Reynolds details the two new studies¾one conducted on humans and the other conducted on rats.

In the human study, elderly women who already had some mild cognitive impairment were split into three groups. One group lifted weights, the second group engaged in moderate aerobic exercise, and the third group did yoga-like activities.

The participants were tested at the beginning and end of the 6-month exercise period and the results were striking. First, bear in mind that, in general, we would expect elderly people who are already experiencing mental decline to continue down that path over time. Indeed, after 6 months, the yoga group (our control group) showed a mild decline in several aspects of verbal memory.

The weight-training and aerobic groups, by contrast, actually *improved* their performance on several tests (remember, this was 6 months later!). In particular, these groups were not losing as much of their older memories and they even became faster at some spatial memory tests involving memorizing the location of three items. In other words, the women were both better at making new memories and better at remembering / retrieving old ones!

### The Math Beast Challenge Problem of the Week – Apr 22, 2013

Note: Figure not drawn to scale.

Quantity A

h

Quantity B8

### Free Events This Week: April 22- April 28

Here are the free GRE events we’re holding this week (All times local unless otherwise specified):

**4/22/13**– Boston, MA- Free Trial Class– 6:30PM – 9:30PM

**4/22/13**– Online – Mondays with Jen– 7:00PM – 8:30PM

**4/25/13**– New York, NY – Free Trial Class- 6:30PM – 9:30PM

Looking for more free events? Check out our Free Events Listing Page.

### Friday Links: Enrollment Decisions,Techniques to Combat Procrastination, &More!

Set the GRE prep work aside for a moment to catch up on some of this week’s top grad school tips and news links:

How to Make the Final Grad School Enrollment Decision (U.S. News Education)

Former dean of admissions has some advice for how to focus your needs and desires when you make your final grad school enrollment decision.

Overcome Procrastination with the Pomodoro Technique (About.com Graduate School)

Looking for a way to overcome procrastination? The Pomodoro Technique is a formal timer-based time management technique”it’s simple and effective.

How to Choose a U.S. Graduate School (U.S. News Education)

Use these four tips to thoroughly research graduate programs and prospective career fields before becoming and international graduate student.

U.S. Graduate Schools Stung by Drop in Chinese Applications (Reuters)

*Reuters* reports that slowing grad school enrollments, including a 5 percent decline in applications from Chine for fall 2013, are hurting the revenues of many U.S. universities.

Did we miss your favorite article from the week? Let us know what you’ve been reading in the comments or tweet @ManhattanPrep

### Using The 5 lb. Book To Study Advanced Quant

I’ve got another one for you from our 5 lb. Book of GRE Practice Problems, and this one’s serious. I took it from the Advanced Quant chapter. Try it out and then we’ll chat!

Triplets Adam, Bruce, and Charlie enter a triathlon. There are nine competitors in the triathlon. If every competitor has an equal chance of winning, and three medals will be awarded, what is the probability that at least two of the triplets will win a medal?

(A) 3/14

(B) 19/84

(C) 11/42

(D) 15/28

(E) 3/4

© ManhattanPrep, 2013

Yuck. I’m not a fan of probability in general and this one is particularly annoying. Why? Because they ask for the probability that *at least two* will win. Most of the time, when a probability question uses *at least* or *at most* language, we can use the cool 1 “ *x* shortcut because there’s only one not-included case.

For example, if I tell you I’m going to flip a coin three times, I might ask you to calculate the probability that I’ll get at least one heads. There’s only one case where I wouldn’t: zero heads. So you can just calculate the probability of zero heads and subtract from 1.

But we can’t do that here, because it’s possible for just 1 twin to win a medal and it’s also possible for zero twins to win a medal. Sigh.

Okay, how are we going to tackle this? Probability is a measure of the number of desired outcomes divided by the total number of possibilities. Let’s figure out the total number of possibilities first.

Take a look at the question again. Is this one of those questions where the order matters? If you don’t win, you don’t win. If you do win, does the question make a distinction between coming in first, second, or third?

### I Feel The Earth Move Under My Feet

Many a true word is said in jest.—I don’t know, but I heard it from my mother.

I moved to Los Angeles, to a little bungalow in Laurel Canyon, the day before the Northridge earthquake. Timing is everything, just like on the GRE. I woke up around 3 in the morning. Because the bungalow was jumping up and down. As a stupid easterner, I thought, Oh, it’s an earthquake. They have them here. I didn’t know it was The Medium One. (It was amazing to see the damage—piles of rubble on Ventura Boulevard and in Hollywood, and the I-10 ramp to the 405 fell down.) As long as I was awake, I decided to go to the bathroom. The first big aftershock threw me into the door frame. It’s unsettling not to have a firm foundation under your feet. You feel out of control and at the mercy of forces larger than you.

And that’s the way students feel about the GRE. And for the same reason, metaphorically speaking. In every GRE class I’ve taught, most of the students were bewitched, bothered, and bewildered by the shakiness of their foundation knowledge. The ground was not firm beneath their feet. It paralyzed them. They understood the concepts of the problems and the relevant strategies to employ, but could not then solve the problems in a timely manner, if at all. Especially on the quant side, the GRE tests a logic system—be precise, don’t assume, pick the choice that must follow. The arithmetic and algebra are the moral equivalent of reading English. You would like to be able to take those skills as much for granted as you do reading words. When I say 7 times 13, you say 91. Think of it as a rap. When you see .625, you say 5/8. Woot. All seriousness aside, people waste 30 seconds a question in the quant because they don’t know their times tables or squares or the fractional decimal percentage equivalencies. Or their algebra isn’t smooth and silky. Think about how much time that uses up during the section. How do you fix that? How do you get to Carnegie Hall? Practice, practice, practice. That’s a New York joke—LA classes hate it. Having that mastery frees you to identify the type, the approach, and the traps—to do what has to be done to score well.

### The Math Beast Challenge Problem of the Week – Apr 15, 2013

Owners of condominiums in a certain community share annual maintenance costs in proportion to their condominium’s share of the total square footage for all community condominiums at the end of the year. In 2011, when total annual maintenance costs were $104,000, the share of these costs for the owner of a 1,000 square foot condominium was $832. In 2012, several new condominiums were added to the community, increasing total annual maintenance costs by $5,000 from the previous year and total development square footage by 3,600 square feet.

In 2012, what was the share of maintenance costs for the owner of the 1,000 square foot condominium?

### But I Studied This – I Should Know How To Do It!

When was the last time you thought that? For me, it was sometime within the past week. I *knew* that this problem was not beyond my reach! Meanwhile, the clock was ticking away and all I could focus on was the fact that I couldn’t remember something that I should have been able to remember.

That horrible, sinking feeling is universal: we’ve all felt it before and “ unfortunately “ we’re all going to feel it again. How can we deal with this?

### Recognize the But! feeling

You almost certainly already know what this feels like, but here’s a longer list of the ways in which this manifests. When was the last time you thought any of these things?

– But I studied this

– But I *should* know how to do this

– If I just had a little more time, I’m *sure* I could figure it out

– I’ve already invested so much time, I don’t want to give up now

– I’ve been struggling with this for 2 minutes but I really did finally figure out *now* what I need to do; it’s just going to take me another 1.5 minutes