# GMAT Question of the Day – Problem Solving – Overlapping Sets/Picking Numbers

At a certain rail-yard each train is either a freight train or a commuter train and either runs on the southern line or the northern line. 20% of the commuter trains run on the southern line and the number of freight trains that run on the southern line represents 20% of the total trains at the rail yard. If the commuter trains represent 44% of the total trains at the rail yard, approximately what percent of the trains run on the northern line?

A. 41%

B. 46%

C. 57%

D. 63%

E. 71%

[spoiler]E.[/spoiler]

## GMAT Question of the Day Solution

These GMAT overlapping sets questions are straightforward but take some organizing so it’s important to take your time with the set-up. On the whole, the GMAT is an organizational challenge. Try picking a value for the total. That should make things easier. Whenever you are dealing with a question that has variables or percents/proportions in the answer choices consider picking numbers to make the question more concrete. Also, did you define what you were looking for: Northern/Total? Defining the question will help you plan your work and will draw you towards the solution.

## More GMAT overlapping sets practice questions!

Here’s an overlapping sets question that adds in a bit of probability. Don’t let the probability component get in your way! Often, probability questions are easy. Take it step by step.

Among a group of 2,500 people, 35 percent invest in municipal bonds, 18 percent invest in oil stocks, and 7 percent invest in both municipal bonds and oil stocks. If 1 person is to be randomly selected from the 2,500 people, what is the probability that the person selected will be one who invests in municipal bonds but NOT in oil stocks?

Here’s a challenging sets question from the GMAT Prep Tests 1 and 2. Stay organized. Make the easy inferences and you should be fine.

In a certain city, 80 percent of the households have cable television, and 60 percent of the households have videocassette recorders. If there are 150,000 households in the city, then the number of households that have both cable television and videocassette recorders could be any number from:

This one is a bit different but will still give you 2 group practice and will give you exposure to overlapping sets on data sufficiency which often comes down to systems of questions/counting equations.

GMAT Question of the Day 2 group overlapping sets Data Sufficiency

Another system of equations/counting equations 2 group overlapping sets question. This one is tough.

GMAT Question of the Day Challenging 2 Group Overlapping Sets Data Sufficiency