Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Magoosh is excited to offer you a free GRE practice test with video answers and explanations. If you’re thinking about taking the GRE or want to see how effective your GRE test prep has been, pinpoint your strengths and weaknesses with this quiz!

This webinar will focus on evaluating reading comprehension questions on the GRE and GMAT. This 60 minute class will be a mix of "presentation" and Q&A where students can get specific questions answered.

This admissions guide will help you plan your best route to a PhD by helping you choose the best programs your goals, secure strong letters of recommendation, strengthen your candidacy, and apply successfully.

Within a group of students, x students are taking English, y [#permalink]
21 Jun 2018, 06:29

1

This post received KUDOS

Expert's post

00:00

Question Stats:

62% (01:13) correct
37% (00:41) wrong based on 37 sessions

Within a group of students, x students are taking English, y students are taking Math, and z students are taking both English and Math. Which of the following represents the number of students who are taking English or Math but not both?

A) x + y - z B) x + y + z C) 2x + 2y - z D) x + y - 2z E) x + y + 2z

Re: Within a group of students, x students are taking English, y [#permalink]
22 Jun 2018, 08:00

1

This post received KUDOS

GreenlightTestPrep wrote:

Within a group of students, x students are taking English, y students are taking Math, and z students are taking both English and Math. Which of the following represents the number of students who are taking English or Math but not both?

Here E = number of students taking English Y= number of students taking Math Z= number of students taking both English and Math

Therefore number of students taking only english = X-Z

and number of student taking only math = Y-Z

Hence number of students who are taking English or Math but not both = (X-Z)+(Y-Z) = X+Y-2Z
_________________

If you found this post useful, please let me know by pressing the Kudos Button

Re: Within a group of students, x students are taking English, y [#permalink]
24 Jun 2018, 06:16

1

This post received KUDOS

Expert's post

GreenlightTestPrep wrote:

Within a group of students, x students are taking English, y students are taking Math, and z students are taking both English and Math. Which of the following represents the number of students who are taking English or Math but not both?

A) x + y - z B) x + y + z C) 2x + 2y - z D) x + y - 2z E) x + y + 2z

We can solve this by using the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions).

Here, we have a population of students, and the two characteristics are: - taking English or not taking English - taking Math or not taking Math

We want to find: (number of students taking English but not Math) + (number of students taking Math but not English) So, we can set up our matrix as follows:

We need to find the number of students in the 2 boxes with stars in them.

GIVEN: x students are taking English, and y students are taking Math So, we can add this information to our diagram as follows:

GIVEN: z students are taking both English and Math So, we can add this information to our diagram as follows:

Let's first examine the top ROW. If a total of x students are taking English, and z of them are also taking Math, then x-z of them are NOT taking Math.

Now examine the left-hand COLUMN. If a total of y students are taking Math, and z of them are also taking English, then y-z of them are NOT taking English.

So, the number of students who are taking English or Math but not both = (x - z) + (y - z) = x + y - 2z

Answer: D

RELATED VIDEO

_________________

Brent Hanneson – Creator of greenlighttestprep.com Sign up for GRE Question of the Dayemails