Problem Solving

Categories : 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

Now if Jim and Tim works together for 1 day then they can do ( 1/N + 1/M ) work in 1 day

So in 1 day then can do (M+N)/M*N

Now lets plug in some real numbers


Categories : Problem Solving

Active Thinking for GMATQuick 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?

Ok. If you answered, or even were tempted to answer, “1.5 carrots,” then I’m glad that you’re reading this article! The thing is, while the bunnies are eating carrots at the rate of one per hour, it doesn’t follow that 1.5 bunnies will eat 1.5 carrots. 1.5 bunnies will only eat one carrot, because 1.5 bunnies is really just 1 bunny. (That half a bunny isn’t feeling very well and doesn’t want any carrots.)

I don’t mean to say that this is a GMAT-style problem, but if you found yourself answering “1.5 carrots,” then you are prone to operating on autopilot. Students who operate on autopilot will often fall into traps, and they may become overwhelmed by questions that don’t fall clearly into easily recognized patterns. And let me tell you – you will likely see many problems on the GMAT that don’t fall into common patterns!

Active Thinking...

GMAT Process of Elimination - Data RangeWhat worries GMAT test takers in Problem Solving is the lengthy calculations, and translation of statements to equations. Lot of students prefers the use of calculators. 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. In order to be successful with this strategy, find out how many answers are close to each other in value. Group them together, and then start with data substitution.

Let us look at an example:

Q) Tim and Phil together can complete the flooring on 2nd floor in 6 days. When Phil was on leave, Tim completed a similar flooring job in 18 days. How long will...

Categories : Problem Solving

GMAT Clock ProblemsClock 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

1 hour  =  360/12 = 30 degrees
60 minutes = 30 degrees
Degrees turned by hour hand in 1 minute = 0.5 degrees

For 1 hour the minute hand completes 360 degrees

1 hour = 360 degrees
60 minutes = 360 degrees
Degrees turned by minute hand in 1 minute = 6 degrees

Lets test what we have learned:

Q) Find the degree between hour hand and minute hand at 3:32'

Hour hand = 3

1 minute ( hour hand) = 0.5 degrees
3 hours = 3*0.5*...

GMAT Weighted AverageAverage Question is an important topic in GMAT problem solving and data sufficiency. Let us start with the Basics.
Average (Arithmetic Mean)

Average of n numbers a1, a2, a3, a4, a5....an

(An) = (a1+a2+.....an) /n

Example: Find the average of 34, 56, 75 and 83


a1 = 34
a2= 56
a4 = 83

Total Number of Elements (n) = 4

Average (An) = (a1+a2+a3+a4)/n
= (34 + 56 + 75 + 83)/4 = 62

Shortcut to Remember:  An x n = a1+a2+.......an

Let us straight away apply this shortcut

Q) The average of four numbers is 20. If one of the numbers is removed, the average of the remaining numbers is 15. What number was removed?

(A) 10
(B) 15
(C) 30
(D) 35
(E) 45


Four Numbers = a1, a2, a3, a4


An = 20

An x n = a1 + a2 + a3 + a4


Categories : GMAT Tips, Problem Solving

GMAT Problem Solving TipsThe 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; in other words, they’ll probably be more like the questions you’re used to seeing on high school and college math tests. The best way to study? Master the basic concepts from geometry, algebra, statistics, and arithmetic — then check out these 10 helpful tips!

1. Make sure your fundamentals are strong.

The GMAT doesn’t allow you to use a calculator—which means you need to be quick and accurate with basic calculations. Be able to multiply and divide decimals. Know common higher powers and roots. Have fractions down to a science: Knowing right away whether 3/8 is less than 5/12 will mean you have more time later to work on more complicated calculations.

2. Choose numbers wisely.

Even questions that don’t contain variables can still be tackled by choosing numbers wisely. For example, if a question asks you about “a multiple of 6,” it’s probably quicker...

Work Rate ProblemsCarefully go through the following question types. These are the standard work rate problems that you would encounter in your GMAT Exam.

Working Together

In questions where individuals work at different speeds, we typically need to add their separate rates together. Make sure you keep your units straight. This doesn’t mean wasting time and writing each and every one out, but rather simply recognizing their existence. Note that 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. Nor, are you averaging or adding the given times taken. You must add rates.

Q) A worker can load 1 full truck in 6 hours. A second worker can load the same truck in 7 hours. If both workers load one truck simultaneously while maintaining their constant rates, approximately how long, in hours, will it take them to fill 1 truck?

A. 0.15
B. 0.31
C. 2.47
D. 3.23
E. 3.25

The rate of worker #1 is 1 truck/6 hours. This can also be 1/6 trucks/1 hour. The rate of worker #2 is 1/7. When together, they will complete 1/6 + 1/...

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