 It is currently 16 Jun 2019, 23:08 GMAT Club Daily Prep

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

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. The value of P if V = 20 and T = 32  Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Founder  Joined: 18 Apr 2015
Posts: 6874
Followers: 114

Kudos [?]: 1332 , given: 6293

The value of P if V = 20 and T = 32 [#permalink]
Expert's post 00:00

Question Stats: 60% (01:06) correct 39% (00:56) wrong based on 38 sessions

For a certain quantity of a gas, pressure P, volume V, and temperature T are related according to the formula PV = kT, where k is a constant.

 Quantity A Quantity B The value of P if V = 20 and T = 32 The value of T if V = 10 and P = 78

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.
[Reveal] Spoiler: OA

_________________

Last edited by Carcass on 04 Oct 2017, 05:36, edited 2 times in total.
Edited by Carcass Director Joined: 03 Sep 2017
Posts: 520
Followers: 1

Kudos [?]: 356  , given: 66

Re: The value of P if V = 20 and T = 32 [#permalink]
1
KUDOS
I've put D because it seemed a nonsense question to me. Is it like that on purpose or is some formula missing? Otherwise, how can I know the value of a variable given two others without knowing their relationship? Founder  Joined: 18 Apr 2015
Posts: 6874
Followers: 114

Kudos [?]: 1332  , given: 6293

Re: The value of P if V = 20 and T = 32 [#permalink]
1
KUDOS
Expert's post
Sorry. I do apologize. I should add the stimulus but internet related problems have been fighting against me.

Regards
_________________
Director Joined: 03 Sep 2017
Posts: 520
Followers: 1

Kudos [?]: 356 , given: 66

Re: The value of P if V = 20 and T = 32 [#permalink]
Using the formula, then we have that column A is equal to $$P=\frac{8}{5}k$$ and column B is equal to $$T=\frac{780}{k}$$. Comparing those two quantities and simplifying we finally reach a comparison between $$k^2$$ and 487.5. Given that k can be whatever constant, we can't say which one of the two is the greatest, thus answer is D!
Director Joined: 09 Nov 2018
Posts: 508
Followers: 0

Kudos [?]: 27 , given: 1

Re: The value of P if V = 20 and T = 32 [#permalink]
IlCreatore wrote:
Using the formula, then we have that column A is equal to $$P=\frac{8}{5}k$$ and column B is equal to $$T=\frac{780}{k}$$. Comparing those two quantities and simplifying we finally reach a comparison between $$k^2$$ and 487.5. Given that k can be whatever constant, we can't say which one of the two is the greatest, thus answer is D!

Just an example:
If k=0, a=0 b=undefined
k=1 makes a=1.6 b=780 GRE Instructor Joined: 10 Apr 2015
Posts: 1962
Followers: 60

Kudos [?]: 1792  , given: 9

Re: The value of P if V = 20 and T = 32 [#permalink]
1
KUDOS
Expert's post
Carcass wrote:

For a certain quantity of a gas, pressure P, volume V, and temperature T are related according to the formula PV = kT, where k is a constant.

 Quantity A Quantity B The value of P if V = 20 and T = 32 The value of T if V = 10 and P = 78

QUANTITY A: The value of P if V = 20 and T = 32
Take given formula, PV = kT, and plug in values to get: P(20) = k(32)
Divide both sides by 20 to get: P = 32k/20
Simplify to get: P = 8k/5

QUANTITY B: The value of T if V = 10 and P = 78
Take given formula, PV = kT, and plug in values to get: (78)(10) = kT
Divide both sides by k to get: (78)(10)/k = T
Simplify to get: T = 780/k

So, we have:
QUANTITY A: 8k/5
QUANTITY B:780/k

Let's TEST some possible values of k

Try k = 1
In this case, we get:
QUANTITY A: 8k/5 = (8)(1)/5 = 8/5
QUANTITY B:780/k = 780/1 = 780
In this case, QUANTITY B IS GREATER

Try k = 1000
In this case, we get:
QUANTITY A: 8k/5 = (8)(1000)/5 = some number greater than 1
QUANTITY B:780/k = 780/1000 = some number less than 1
In this case, QUANTITY A IS GREATER

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com Intern Joined: 02 Oct 2018
Posts: 31
Followers: 0

Kudos [?]: 2 , given: 0

Re: The value of P if V = 20 and T = 32 [#permalink]
In the first case it becomes P=1.6k whereas in the second case it becomes 780/k.

Since we don't know k we can't determine the answer. Re: The value of P if V = 20 and T = 32   [#permalink] 13 Nov 2018, 08:34
Display posts from previous: Sort by

The value of P if V = 20 and T = 32  Question banks Downloads My Bookmarks Reviews Important topics Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.