# GMAT Problem Solving: Method, Example and Traps | topin

GMAT guidesProblem Solving

Section

Quantitative Reasoning

Questions

All 21 Quant questions, in 45 minutes

Time per question

Just over 2 minutes on average

Format

Five answer choices, one correct

Calculator

None; the numbers are built to work by hand

Content

Arithmetic and algebra, many word problems; no geometry

## How it works

Each question gives you a problem, often a word problem, and five answer choices. Topics include number properties, percents, ratios, rates, equations, inequalities, exponents, counting, probability and statistics. The section adapts after every question, so the difficulty you see depends on how you are doing.

## Worked example

If x and y are positive integers and 3x + 5y = 52, how many different pairs (x, y) are possible?

1. A2
2. B3
3. C4
4. D5
5. E6
Show the answer

B: 3

Test y rather than x, because 5y moves in bigger steps. 52 - 5y must be positive and divisible by 3\. y = 1 gives 47, no. y = 2 gives 42, so x = 14\. y = 3 gives 37, no. y = 4 gives 32, no. y = 5 gives 27, so x = 9\. y = 6 and y = 7 give 22 and 17, no. y = 8 gives 12, so x = 4\. y = 9 and y = 10 give 7 and 2, no, and y = 11 makes x negative. That leaves (14, 2), (9, 5) and (4, 8). Once you find one solution, the others follow by adding 3 to y and taking 5 from x. The trap is counting every y up to 10 that keeps x positive without checking divisibility.

## A method for Problem Solving

1. 1  
### Read the last line first  
Note exactly what is asked: x, 2x, x + y, a percentage or a count. Writing the target on your scratch board stops you solving for the wrong thing.
2. 2  
### Scan the answer choices  
Choices that are far apart invite estimation. Choices written in variables invite picking simple numbers. Choices close together mean you need an exact calculation.
3. 3  
### Translate before you calculate  
Turn each sentence into an equation or a short note. Watch for phrases that change the maths, such as 'percent of' versus 'percent more than', or 'at least' versus 'more than'.
4. 4  
### Simplify before you multiply  
Cancel common factors, factorise and use known fraction and percent equivalents. GMAT arithmetic is built to cancel, so long multiplication usually means a missed shortcut.
5. 5  
### Check the answer against the question  
Plug your answer back in or test it against the conditions, including any integer or positive constraint. This takes seconds and catches most slips.
6. 6  
### Cut and guess when stuck  
With no plan after about 30 seconds, eliminate what you can, choose from what is left and move on. Unanswered questions at the end cost more than one guess.

## Traps to avoid

* Answering an intermediate value, such as x, when the question asks for x + y or a percentage change.
* Forgetting cases in number properties: negatives, zero, fractions or non-integers when the question does not rule them out.
* Adding percentage changes together, for example treating a 25% rise then a 20% fall as a 5% rise when it is no change at all.
* Picking the answer that matches a partial count or one case of an 'or' condition.
* Spending four or five minutes on one hard question and then rushing the rest of the section.

## Problem Solving FAQs

Are there Data Sufficiency questions in GMAT Focus Quant?

No. Quant is Problem Solving only. Data Sufficiency moved to the Data Insights section.

How long should I spend on a GMAT Problem Solving question?

About two minutes on average, since the section is 21 questions in 45 minutes. Some will take one minute and a few three, but cut anything that passes three minutes.

Can I use a calculator for GMAT Problem Solving?

No. Quant has no calculator, so practise mental arithmetic, fraction and percent equivalents and simplifying before you calculate.

Is geometry on the GMAT Focus Edition?

No. Problem Solving now covers arithmetic and algebra only, so you can skip geometry formulas in your preparation.

Should I pick numbers or use algebra on GMAT Quant?

Both are useful. Pick numbers when the choices are expressions in variables or percentages of an unknown total, and use algebra when there is a clear equation to solve.

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