Last visit was: 25 Nov 2024, 01:05 It is currently 25 Nov 2024, 01:05

Close

GRE Prep 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
Your Progress

every week, we’ll send you an estimated GRE 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.

Close

Request Expert Reply

Confirm Cancel
User avatar
Retired Moderator
Joined: 07 Jun 2014
Posts: 4813
Own Kudos [?]: 11197 [4]
Given Kudos: 0
GRE 1: Q167 V156
WE:Business Development (Energy and Utilities)
Send PM
avatar
Retired Moderator
Joined: 20 Apr 2016
Posts: 1307
Own Kudos [?]: 2273 [2]
Given Kudos: 251
WE:Engineering (Energy and Utilities)
Send PM
User avatar
Retired Moderator
Joined: 07 Jun 2014
Posts: 4813
Own Kudos [?]: 11197 [0]
Given Kudos: 0
GRE 1: Q167 V156
WE:Business Development (Energy and Utilities)
Send PM
User avatar
Director
Director
Joined: 22 Jun 2019
Posts: 521
Own Kudos [?]: 711 [2]
Given Kudos: 161
Send PM
Re: a = 2b = 4c and a, b, and c are integers. [#permalink]
2
sandy wrote:
Explanation

Since a is common to both quantities, it can be ignored. The comparison is really between b and c.

Because 2b = 4c, it is true that b = 2c, so the comparison is really between 2c and c. Watch out for negatives. If the variables are positive, Quantity A is greater, but if the variables are negative, Quantity B is greater.



So, the comparison is really between 2c and c.

Why not we cancel both C from both side and rest we get 2 and 1. So A is greater !!!!!!!!!!!!!!!!
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Own Kudos [?]: 12197 [1]
Given Kudos: 136
Send PM
Re: a = 2b = 4c and a, b, and c are integers. [#permalink]
1
sandy wrote:
a = 2b = 4c and a, b, and c are integers.

Quantity A
Quantity B
\(a + b\)
\(a + c\)


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


Sometimes a quick approach is looking for values that make the two quantities equal (see video below).

So, for example, it could be the case that a = b = c = 0, In which case the two quantities are equal.
It could be the case that a = 4, b = 2 and c = 1, In which case the two quantities are NOT equal.

Answer: D

RELATED VIDEO
GRE Instructor
Joined: 24 Dec 2018
Posts: 1065
Own Kudos [?]: 1426 [0]
Given Kudos: 24
Send PM
Re: a = 2b = 4c and a, b, and c are integers. [#permalink]
huda wrote:
sandy wrote:
Explanation

Since a is common to both quantities, it can be ignored. The comparison is really between b and c.

Because 2b = 4c, it is true that b = 2c, so the comparison is really between 2c and c. Watch out for negatives. If the variables are positive, Quantity A is greater, but if the variables are negative, Quantity B is greater.



So, the comparison is really between 2c and c.

Why not we cancel both C from both side and rest we get 2 and 1. So A is greater !!!!!!!!!!!!!!!!


Because \(c\) can be negative or positive. You can cancel \(c\) from both sides only when you are hundred percent sure the value of \(c\) is positive.
GRE Instructor
Joined: 24 Dec 2018
Posts: 1065
Own Kudos [?]: 1426 [1]
Given Kudos: 24
Send PM
a = 2b = 4c and a, b, and c are integers. [#permalink]
1
If \(a,b \text{ and } c \text{ are positive }\), then

\(a=2b\)

\(b = \frac{a}{2}\)

\(a = 4c \)

\(c = \frac{a}{4}\)

\(Quantity A = a + \frac{a}{2}\)

\(Quantity B = a + \frac{a}{4}\)

Clearly \(Quantity A > Quantity B\)

But if \(a,b \text{ and } c \text{ are negative }\), we are going to get the opposite

\(Quantity A = -a -\frac{a}{2}\)

\(Quantity B = -a -\frac{a}{4}\)

Clearly \(Quantity B > Quantity A\)

The answer is D. There exists no relationship between the two quantities.
Prep Club for GRE Bot
a = 2b = 4c and a, b, and c are integers. [#permalink]
Moderators:
GRE Instructor
84 posts
GRE Forum Moderator
37 posts
Moderator
1111 posts
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne