Problem Solving

Work problem is another common topic tested during GMAT . About 2-4 questions are asked from this topic. Work is a specific task assigned to one or more persons that are required to be completed in 'n' amount of time.

Here n is represented as days.

Suppose Jim works for N days then he can do 1/N of the work in 1 day
Suppose Tim work for M days then he can do 1/M of the work in 1 day

Read the Complete Tutorial

Quick brainteaser for you: If 3 bunnies can eat 3 carrots in one hour, how many carrots can 1.5 bunnies eat in one hour? 

Really take a moment to think about it.

Do you have an answer?

If you have started solving a few GMAT PS questions, you might have realized that solving some of the toughest GMAT 800 questions does not require even solving them in a traditional manner.

Process of Elimination is an often-neglected technique when it comes to solving time consuming and tricky GMAT Problem solving questions.

In this article, we will cover how to classify answer choices into groups, and guess the probable range of the answer based on the facts provided in the question

Clock based math problems are among the most challenging and interesting problems to crack.

For every 60 units that a minute hand move in an hour, the hour hand moves 5 units.

For 12 hours the hour hand completes 360 degrees.

Now, learn how these two information can help you solve any GMAT Clock Problems.

Average Question is an important topic in GMAT problem solving and data sufficiency. Let us start with the Basics.When we have groups of numbers whose individual averages are known then Weighted Averages will help us find the average of the entire group.

The Tutorial includes tips to solve Average Age questions and other weighted average questions.
 

The Problem Solving (PS) section of the GMAT may not be as quirky as the Data Sufficiency section of the test – but that doesn’t mean you don’t need to study for it! PS questions require more “straight math” than Data Sufficiency questions. Find out the 10 Tips to Solve GMAT Problem Solving Questions

In questions where individuals work at different speeds, we typically need to add their separate rates together. When working together, the total time to complete the same task will be less than BOTH of the individual rates, but not necessarily in proportion. You must add rates.

Learn more about Work-Rate Problems!

Simple interest and compound interest - essential topics for an MBA. GMAC thinks the same too. So you will find these questions randomly distributed in your GMAT Exam. The key to deciphering between compound interest and simple interest is to see how many periods the interest is paid….interest paid in one period is simple interest and interest “paid on interest” in multiple periods is compound interest. Learn More!

Learn the concepts behind volume and surface area before you start solving GMAT Solid geometry problems. All solid geometry problems come down to this - length, breadth and height.

For data sufficiency questions, look out for values of l, b and h. if any of them are missing then it would be easy to eliminate answer choices. Here is How!

GMAT Number properties may sound scary, but they just constitute elementary mathematical principles.

You probably know most of these principles by memory; if not, you could easily execute a calculation to ascertain them.

The GMAT Quantitative section is all about saving time; making number theory second nature will definitely save you some valuable seconds. Here is how!

Word problems on the GMAT get an unfair reputation for being especially challenging. However, it’s helpful to think of them as just dressed-up algebra. The real challenge is that they are (1) long, (2) boring, and (3) require translation from ‘English’ to ‘Math.’  Here are a few questions to ask yourself to make sure you fully break down and understand the problem BEFORE you start to solve!. Learn how to solve Word Problems in GMAT.

Even if you fear statistics by its reputation, it is one of the easiest sections in the GMAT because a standard set of questions is asked and anyone who understands the fundamentals that I shall describe will be able to ace the questions. Learn the GMAT Statistics Fundamentals.

One of the smallest and least noteworthy words in the English language, the word “of” is crucial to your success on the GMAT, on both the quantitative and verbal sides of the exam. Learn Why!

Backsolving is a technique of trying out the answer choices in the question. Each choice is selected one at a time and is assumed to be the right choice. Analyze the value or conditions by injecting the choices into the question. Backsolving is incredibly time saving in algebraic equations and number properties problems.

Case 1: To find the value of an equation
Example: Which number gives the lowest value for the equation?
1/X + (1/X) ^2 + 5X

Approach 1: Start from the middle value in the answer choice.
For example, if the five answer choices are 14,5,19,8,21

Plug 14 into the equation and check the value. If the value is too high, find out an answer choice with a much smaller value, like 5.

Approach 2:  If you inspect the equation, the first two terms will result in small numbers, smaller than 1, according to the given answer choices. However, the 3rd term of the equation is the leading one. A small value in 5X will make the equation’s net value smaller, and a big value in 5X will make the equation’s net value bigger. So, the answer is almost immediately x = 5.


Case 2: To satisfy a condition
Example: If y # 3 and 2x/y is a prime integer greater than 2, which of the following must be true?

I. x = y
II. y = 1
III. x and y are prime integers.

(A) None

(B) I only

(C) II only

(D) III only

(E) I and II

Recommended Books

1. Kaplan GMAT Math Workbook
2. Kaplan GMAT 800: Advanced Prep for Advanced Students (Kaplan Gmat Advanced)

Standard Deviation of a probability distribution measures the distribution of data from the mean value. Probability distribution maps the probability of a variable within a particular range of values.

For Example: Suppose we toss a coin two times

All possible outcomes: HH, HT, TH, TT
Total number of outcomes = 4
Let a variable, X measures the number of heads in this experiment
Probability of n heads = (Outcomess with n heads)/ (Total number of outcomes)

Number of Heads                  Probability
 (X)                                 (Probability of n heads)             
 
    0                                  0.5                                                 
    1                                  0.25
    2                                  0.25

For a probability distribution, plot number of Heads(X) on the x-axis and the probability of n heads on the y-axis.

Range of values in this case = 0-2

Variance is the square of standard deviation = SD ^ 2 = 14.59

For Complete Set:  Divide the sum of the resulting values with the number of elements in the data set and find the square root

If you understand the following key concepts then questions on speed and distance, especially problems on train are