Tag Archives: quantitative

GMAT Quant: Question of the Day!

Try Picking Numbers with the GMAT practice problem of the day!

Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m. By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?

A. k/m
B. (k – m)
C. [100 (k – m)]/ (100 + k)
D. [100 (k – m)]/(100 + m)
E. [100 (k – m)]/ (100 + k + m)

—
If the original price per share of Stock X = 100
Let’s say k = 20
New price per share = 120

Original earnings per share of Stock X = 100
Let’s say m = 5 (since k > m)
New earnings per share = 105

Old ratio of price/earnings = 100/100 = 1
New ratio of price/earnings = 120/105 = approx 1.14

The percent increase is approx 14%.

Plug in our numbers into the answer choices, and look for the choice that also yields 14%:

A. k/m = 20/5 = 4 too small

B. (k – m) = 20 – 5 = 15 too big

C. 100 (15) / 100 + 20 = 1500 / 120 = 12.5 too small

D. 100 (15) / 100 + 5 = 1500/105 = approx 14. CORRECT!

E. 100 (15) / 100 + 20 + 5 = 1500/125 = 12

The answer is (D).

Advertisement

Using Strategy on the GMAT to Improve your Score

When a GMAT student asks me, “What can I do to get better scores?” usually the first thing I ask is, “What is your current strategy?” Most of the time, I get a pretty vague response. Reading about strategy is the OG, on the BTG forum, or in a GMAT book is NOT the same as actually having a solid strategy. The word “strategy” may sound fuzzy, but all it means is a simple step-by-step approach for each unique question type.

Not only do you have to choose a strategy that works for you, but you have to implement it every time, practicing enough so that is becomes second-hand. Ballet dancers practice a pirouette millions of times, so that when they perform onstage they don’t have to think about it. You want to do the same thing for GMAT.

Before you sit down to take your next diagnostic on GMATPrep, quickly review this strategy cheat sheet (or make one of your own). These methods may not necessarily work for you, but you’ll only learn what does through trial and error. For more in-depth discussion on each of these strategies, search my other posts.

Verbal

Reading Comprehension –

1. Break down the passage. 2. Rephrase the question. 3. Predict an answer. 4. Eliminate.

Critical Reasoning –

1. Identify the Conclusion, Evidence & Assumptions. 2. Rephrase the question. 3. Predict and answer.

Sentence Correction –

1. Spot the primary error. 2. Eliminate answer choices that do not fix. 3. Look for secondary errors and eliminate.

Quant

Problem Solving –

1. Write down the given information. 2. Scan the answer choices. 3. Look for ways to pick numbers or plug in. 4. Recall relevant formulas. 5. Solve.

Data Sufficiency –

1. Identify the type of DS. 2. Determine what is needed for sufficiency. 3. Evaluate statements independently. 4. Combine if needed.

Ratios and Proportions on the GMAT

A ratio expresses the relationship between two or more things. A proportion is a relationship that is formed by setting two ratios equal. Learn how to solve proportion problems using equivalent ratios on the GMAT….like a rockstar on this Learnboard!

Once you’ve reviewed the board, try this Data Sufficiency problem on your own:

For each month, the number of accounts, a, that a certain salesman has contracted that month is directly proportional to his efficiency score, e, which is directly proportional to his commission rate, c. What is a if c = 3.0?

(1) Whenever c = 4.0, e = 0.3

(2) Whenever c = 6.0, a = 80

Explanation:

It will be helpful to first note that because a is directly proportional to e, which is in turn directly proportional to c, a is then directly proportional to c. To say that a is directly proportional to c is just to say that there is a constant k such that ck = a, or, perhaps more simply, that there is a fixed ratio between a and c. A statement, or set of statements, will be sufficient if and only if it determines that ratio.

Statement (1): From this, the proportional relationship between e and c can be determined. However, a is directly proportional to e, and nothing is said about that relationship; therefore, the value of a when c = 3.0 cannot be found; NOT sufficient.

Statement (2): This gives you the ratio you want. You don’t need to actually calculate the value of a if c = 3.0. You just need to know that it’s possible. Don’t believe me? Because a is directly proportional to c: a/c = 80/6.0. Since the question asks for the value of a when c = 3.0, divide the numerator and denominator each be 2. a = 40. Or, if you’re determined to cross multiply: substitute the given value for c: a/3.0 = 80/6.0. By cross multiplication, 6a = 240. Therefore, a = 40; SUFFICIENT. The credited response is B.

Tricky Triangles: the GMAT’s Favorite Shape!

A triangle is a three-sided shape whose three inner angles must sum to 180°. The largest angle will always be across from the longest side. Triangles are the most commonly-tested geometry topic on the GMAT!

Remember the sum of all the interior angles in a triangle will sum to 180 degrees, so you can always solve for the third angle if you know the other two.

If you’re told two triangles are similar, the corresponding angles are congruent, or equal. You can set up various proportions to the corresponding sides as well.

More essential info:essential info: the side of any triangle must be BETWEEN the sum and the difference of the other two sides.

Check out some practice problems to refresh your triangle properties on this Learnboard!

Contrast Words in GMAT Sentence Correction

Contrast keywords are fairly common on GMAT Sentence Correction questions. Some of the most common words you’ll see include:

  • but
  • however
  • on the other hand
  • unlike
  • in contrast to
  • different from
  • whereas
  • while
  • yet
  • as opposed to

Let’s look at an example question now

However a minimal role in causing air pollution, trash pollutes both land and sea, creates problems in wildlife habitats, and harms endangered species

A) However
B) With
C) Being
D) Therefore accounting for
E ) Despite playing

—

Here we have the phrases “minimal role” and “trash pollutes..creates problems…harms…” which tells us we’ll need a Contrast word to open the sentence. (B), (C), and (D) do not provide a contrast, so we can quickly eliminate them.

Between (A) and (E), (E) is the better choice since “However a minimal role…” is an awkward construction. A better way to use “however” here would be: However minimal its role….

Tough GMAT: Question of the Day!

This challenging CR question requires us to make an inference based on the passages. Inference questions are among the most-challenging Critical Reasoning problems.

Improved technology and equipment often result in fewer injuries during high-risk activities such as rock climbing and scuba diving. But participant education also plays a large role in reducing the number of injuries sustained during these activities. People who are poorly trained in these activities run a much higher risk of injury even if provided with the latest and best equipment.

Which of the following can be properly inferred from the information above?

A) Training is a more important safety factor than equipment in high-risk activities.
B) People who are properly trained in their activities do not sustain injuries.
C) The safety benefits of the latest equipment can be offset by inadequate preparation.
D) Rock climbing and scuba diving are more risky than any other activities.
E) People with the latest equipment often neglect proper training.

—

Here’s how I took the argument apart, on my yellow scratch-pad. 🙂

Conclusion: Poor training = higher risk of injury EVEN with equipment

Evidence: Participant education plays a “large role”

Assumption: The equipment resulting in “fewer injuries” only applies when people have been trained

Question Rephrase: What is BASED on the conclusion/evidence?

Prediction: Correct answer must connect the fewer injuries with the participant education training.

The closest choices are (A) and (C). If the conclusion says that there is high risk even WITH the equipment, then this best supports (C) since it is obvious the equipment itself it not preventing injuries.

The relative “importance” of the safety factors is not a part of the argument. The RISK is higher w/o training, even with equipment, but as the others have mentioned no comparison between training and equipment is made.

The answer is (C).

10 Ways to Study for the GMAT in Just 30 Days

It’s possible to get a great GMAT score after only 1 month of study, but it requires hard work and discipline. In the middle of applying for scholarships and filling out MBA applications, you’ll need to devote a good amount of time to your GMAT practice as you’ll be cramming what is typically a 2-3 month process into just one! There are excellent GMAT resources online: from free GMAT practice tests to great Test Prep articles. Follow these GMAT study tips to maximize the free GMAT resources for better scores in just one month!

1. Start with the Official Guide. Learn the format, content, and do a general overview of the GMAT test itself using the OG 12th editions. Make sure to go to MBA.com and

2. Study every day, and don’t procrastinate! You will need to be disciplined about your studies. Work backwards from your test date. Don’t cram on the weekends only! With only one month to study, you’ll need to do at least some GMAT every single day.

3. Use MGMAT SC & Powerscore CR to supplement your materials. After the OG, these are two Verbal books that can take your score to the next level.

4. Join Grockit, and Beat the GMAT. These online GMAT sites are vital to building your comfort level with the computer-based format of the GMAT. Practicing in the test-format will only increase your chances of doing well!

5. Study in short, intensive blocks. GMAT study blocks that are too long will ultimately wear you down. Make sure to rotate your study topics often and abide by it, even if you’d like to squeeze in a few more hours. Staying up all night to complete yet another practice test is not always the best choice.

6. Track down success stories to get inspired. If you have a 600 and are eyeing a 700+ score, there are many people out there who have made that leap. Success leaves footprints. Find out what strategies are commonly used by 750+ students, what study plans they keep, and how they build their content-knowledge. Beat the GMAT is an excellent tool for this!

7. Create an Error Log. Re-take quizzes and practice tests from the very beginning of your GMAT studies. Do you find yourself getting the same questions incorrect? This can be a sign that you haven’t learned the content you think you have. Be honest with yourself about what is “sinking in” and what is not. Use an Error Log to assess. You can find many templates online

8. Review all questions. Use the 40/60 rule. 40% of your time should be spent actually answering questions. At minimum, 60% of your time should be spent reviewing.

9. Take at least 1 GMAT practice test per week. Don’t take your practice tests sitting cross-legged on you bed. Utilize your desk and scratch pad as you would on the actual test. Your body needs to adjust to what it feels like to take a 3+ hour test. Because you only have one month to prepare, you should plan to take 4 practice tests, although 6 would be ideal.

10. Use a strategy for each question type. Not only do you have to choose a strategy that works for you, but you have to implement it every time, practicing enough so that is becomes second-hand. Ballet dancers practice a pirouette millions of times, so that when they perform onstage they don’t have to think about it. You want to do the same thing for GMAT.

GMAT Quant: Question of the Day!

Today let’s work on a sets problem using Venn diagrams!

In 1997, N people graduated from college. If 1/3 of them received a degree in the applied sciences, and, of those, 1/4 graduated from a school in one of six northeastern states, which of the following expressions represents the number of people who graduated from college in 1997 who did not both receive a degree in the applied sciences and graduate from a school in one of six northeastern states?

(A) 11N/12
(B) 7N/12
(C) 5N/12
(D) 6N/7
(E) N/7

This question can be solved using a Venn diagram or a matrix to make sense of the information:

The key to understanding this question lies in the last sentence:

who did not both receive a degree in the applied sciences and graduate from a school in one of six northeastern states?

We have two categories to sum: the people who ONLY received a science degree but NOT from one of the 6 schools, and the people who ONLY went to the 6 schools but did NOT receive a science degree. I made up variables for these categories (x and y).

If N = 12, there are 4 applied science students, 1 of which is both. That means x = 3. If 4 students are applied science, then 12-4 = 8 are from one of the six states but NOT applied science. y = 8.

3 + 8 = 11

So we are looking for an answer choice that gives us 11 when N = 12; the answer is (A).

What’s the Triangle Inequality Theorem?

Triangle Inequality Theorem is fair game on the SAT, ACT, GRE, or GMAT. It’s often forgotten by test-takers, but when it pops up, you’ll be glad you know it! The theorem essentially states that the third side of a triangle must be between the difference and sum of the other two sides.

For example, if we had a triangle in which two sides were 6 and 9, then the third side must be between 3 (9-6) and 15 (9+6). The third side cannot actually equal 3 or 15, it’s important to remember.

Let’s try a practice question utilizing this math rule!

If two sides of a triangle have lengths 2 and 5, which of the following could be the perimeter of the triangle?

I. 9
II. 15
III. 19

A) None
B) I only
C) II only
D) II and III only
E) I,II and III
—

If two of the sides are 2 and 5. Then the range of possible values for the third side can be expressed as:

3 < x < 7

Perimeter is the sum of the sides. Let’s choose 3 and 7 as values for the 3rd side (even though we know they are the end-limits only) to create a range for the perimeter.

On the low end:

2 + 5 + 3 = 10

On the upper end:

2 + 5 + 7 = 14

So the perimeter range can be expressed as:

10 < x < 14

The perimeter must be BETWEEN 10 and 14. The answer is (A).

Here’s a link to a lot of great Triangle review topics if you want more Geometry practice: http://www.beatthegmat.com/mba/category/tags/gmat-math/geometry/triangles.

SAT Math: Question of the Day!

It’s been awhile since we took a look at an SAT word problem! Let’s try one out today!

Three types of pencils J, K, and L cost $0.05, $0.10, and $0.25. If a box of 32 of these pencils costs a total of $3.40 and if there are twice as many K pencils as L pencils in the box, how many J pencils are there?

A) 6
B) 12
C) 14
D) 18
E) 20

—

.05j + .10k + .25l = $3.40

j + k + l = 32

2l = k

Plug the third equation into the 1st and 2nd equations and simplify:

.05j + .2l + .25l = 3.40
.05j + .45l = 3.40
5j + 45l = 340
j + 9l = 68

j + 2l + l = 32
j + 3l = 32

Now we have two equations with two variables. We can solve for j.

j + 9l = 68
– (j + 3l = 32)

6l = 36
l = 6

Plug l back in to solve for j.

j + 9(6) = 68
j + 54 = 68
j = 14

The answer is (C).