What is number sense and how can you recognize number sense problems on the GMAT? Before we get into the details, let’s start with a few number sense practice problems. Remember, no calculator. Warm-Up Problems 1) Rank those three in order from smallest to biggest. (A) I, II, III (B) I, III, II (C) II, I, […]

# Archive | Quant Strategies

## GMAT Tricks with Systems of Equations: Part 5

A lot of GMAT test-takers vaguely remember a rule from high school, that it’s possible to solve for two variables if and only if you’re given two equations, and generally that it’s possible to solve for n variables if and only if you’re given n equations. Unfortunately, that rule isn’t quite correct as written, and […]

## GMAT Tricks with Systems of Equations: Part 4

A lot of GMAT test-takers vaguely remember a rule from high school, that it’s possible to solve for two variables if and only if you’re given two equations, and generally that it’s possible to solve for n variables if and only if you’re given n equations. Unfortunately, that rule isn’t quite correct as written, and […]

## GMAT Tricks with Systems of Equations: Part 3

A lot of GMAT test-takers vaguely remember a rule from high school, that it’s possible to solve for two variables if and only if you’re given two equations, and generally that it’s possible to solve for n variables if and only if you’re given n equations. Unfortunately, that rule isn’t quite correct as written, and […]

## GMAT Tricks with Systems of Equations: Part 2

A lot of GMAT test-takers vaguely remember a rule from high school, that it’s possible to solve for two variables if and only if you’re given two equations, and generally that it’s possible to solve for n variables if and only if you’re given n equations. Applying this rule incorrectly causes quite a few errors […]

## GMAT Tricks with Systems of Equations: Part 1

## The Word “Or” in GMAT Math

Consider the following scenario. Suppose you solve for all the numbers in a Venn Diagram, in a scenario in which 200 students are taking AP Chemistry, AP Literature, both, or neither. Here are the results you find. OK, from this solved Venn diagram, there’s a ton we know: total in AP Chemistry = 50 + […]

## One More RTD Table Problem: Average Rates Part 2

If you haven’t been following our series on RTD tables, take a few minutes to catch up: Using Diagrams to Solve Rate Problems: Part 1 Using Diagrams to Solve Rate Problems: Part 2 A Different Use of the RTD Table: Part 1 A Different Use of the RTD Table: Part 2 Using the RTD Table […]

## Using the RTD Table for a Complicated Problem

My last few blog posts have involved rate problems about simultaneous movement. In each of these problems we discovered exactly two travelers who either (1) moved at their own constant rates for the entire time period covered by the story, or (2) moved at their own constant rates and started and stopped simultaneously. If you’d […]

## A Different Use of the RTD Table: Part 2

Let’s recap where we left off yesterday. We were working with this diagram: We wanted to solve for Mary’s time, t. In every row the relationship among rate, time, and distance is the same: RT=D. In this diagram the bottom row looks the most promising, since it alone contains only the variable for which we’re […]