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.

This period of time is long enough: it gives you more than enough time to comfortably learn, review and practice all of the material. On the other hand it is not too long.

Free GRE Class: First Session. Experience the power of live instruction, for free. Our sample classes showcase our passionate and dedicated faculty and the way they'll guide you through proven strategies for improving your score.

QOTD#20 List X: 2, 5, s, t List Y: 2, 5, t The average [#permalink]
07 Sep 2016, 12:57

Expert's post

00:00

Question Stats:

42% (01:23) correct
57% (01:21) wrong based on 28 sessions

List X: 2, 5, s, t List Y: 2, 5, t

The average (arithmetic mean) of the numbers in list X is equal to the average of the numbers in list Y.

Quantity A

Quantity B

s

0

A) Quantity A is greater. B) Quantity B is greater. C) The two quantities are equal. D) The relationship cannot be determined from the information given

Re: QOTD#20 List X: 2, 5, s, t List Y: 2, 5, t The average [#permalink]
07 Sep 2016, 13:01

Expert's post

Explanation

Since you are given that the average of the 4 numbers in list X is equal to the average of the 3 numbers in list Y, it follows that \(\frac{(2+5+s+t)}{4} = \frac{(2+5+t)}{3}\). To make it easier to compare Quantity A and Quantity B, you can simplify this equation as follows.

From the equation 3s = 7 + t, if t = –7, then s = 0, but if t = 0, then s > 0. In one case, the quantities are equal, and in the other case, Quantity A is greater. Therefore the correct answer is Choice D. _________________

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

Re: QOTD#20 List X: 2, 5, s, t List Y: 2, 5, t The average [#permalink]
12 Jun 2019, 07:12

Expert's post

sandy wrote:

List X: 2, 5, s, t List Y: 2, 5, t

The average (arithmetic mean) of the numbers in list X is equal to the average of the numbers in list Y.

Quantity A

Quantity B

s

0

A) Quantity A is greater. B) Quantity B is greater. C) The two quantities are equal. D) The relationship cannot be determined from the information given

Another approach is to test some values.

Let t = -7 This means list Y is 2, 5, -7, so list Y has an average of 0 For list X to have an average of 0, s must = 0 In this case, quantity A and quantity B are equal.

Let t = 2 This means list Y is 2, 5, 2, so list Y has an average of 3 For list X to have an average of 3, s must = 3 In this case, quantity A is greater than quantity B

Answer: D

RELATED VIDEO

_________________

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

greprepclubot

Re: QOTD#20 List X: 2, 5, s, t List Y: 2, 5, t The average
[#permalink]
12 Jun 2019, 07:12