Here’s the answer from Monday’s Brain Twister! A math teacher assigns a distinct prime number, starting with the lowest, for each student in her class. If she chooses two students at random, the probability the sum of their numbers is not even is less than 1/10. What is the fewest possible number of students in […]

# Author Archive | Chris Lele

## GRE Brain Twister: A Prime Example

Here’s this month’s GRE Brain Twister! Try to answer it in the comments below, and we’ll post the answer on Thursday! A math teacher assigns a distinct prime number, starting with the lowest, for each student in her class. If she chooses two students at random, the probability the sum of their numbers is not […]

## GRE Vocab Wednesday: Vocabulary from Article of the Month (Part I)

The first of the two articles in this article of the month was such a cornucopia of words that I have split into two vocabulary Wednesday posts. If you haven’t read the articles, I highly recommend them. It’s a different format than usual; it’s a debate of sorts, in which I pit two perspectives against […]

## GRE Vocab Wednesday: “Con”-notations (and Denotations!)

Con- is a tricky root because people often think of “pros” and “cons”, and that con- therefore means “against”, like the root “contra”. “Con-“ actually means “with”, but that usually won’t help you much since the roots that follow “con-“ are usually pretty esoteric. It is better to learn the definition of these “con-“ words. […]

## Articles of the Month – Battle of the Grammarians

In the left corner, weighing in with a Harvard doctorate degree in philosophy and a tenured position at the university, is intellectual rock star, Stephen Pinker-author of such bestselling books as The Blank Slate and The Language Instinct. In the right corner, weighing in with the irreproachable intellectual organ that is the New Yorker, is […]

## GRE Brain Twister – Watch out for the Trap(ezoid)! (Answer)

Here’s the answer to Monday’s Brain Twister! *Figure not drawn to scale Given that angle ACD and angle BDC are less than 90, what is the smallest possible area of trapezoid ABCD* in which the height each side is a different integer length? Explanation: A good way to get the answer is to play around […]

## GRE Brain Twister – Watch out for the Trap(ezoid)!

Here’s this week’s Brain Twister! The answer will be revealed on Thursday. *Figure not drawn to scale Given that angle ACD and angle BDC are less than 90, what is the smallest possible area of trapezoid ABCD* in which the height each side is a different integer length? Numeric Entry: _________________

## GRE Brain Twister – Prime Time (Answer)

Explanation: We can’t just write down any prime number; we need to make sure that when you subtract one prime number from the others that you get a prime number. Since every prime number except for ‘2’ is odd, when you subtract a prime number by a prime number you will end up with an […]

## GRE Vocab Wednesday: J-Words

the lexical sun. Well, let me redress that omission with the five GRE ‘J’ words below. Also, in keeping with the change I inaugurated in the previous Vocab Wednesday, I will be starting off each entry with an example sentence, so you will be able to guess the meaning. My hope is that extra little […]

## GRE Brain Twister – Prime Time

Terrence writes down one of the numbers from 0-20 on one index card each until he has written each number exactly once and then faces all the cards down. Next, he randomly chooses two cards without turning them over. What is the probability that a prime number will be written on each card and that […]