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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Sep 28Live Online Class with Top GRE Expert Mike Butville
08:00 PM EDT
-10:00 PM EDT
Top scores are possible when you enroll in a powerful GRE course, taught live online + 6 months access to TTP GRE OnDemand video courses included! Class starts Mon/Wed Sept. 28, 2026 - Dec. 9, 2026, 8:00pm-10:00pm EST
Which is greater a+d or b+c
[#permalink]
25 Dec 2018, 10:44
25 Dec 2018, 10:44
1
Expert Reply
7
Bookmarks
00:00
Question Stats:
58% (01:05) correct
41% (00:59) wrong based on 177 sessions
Hide Show timer Statistics
\(\frac{a}{b}= \frac{3}{7} = \frac{c}{d}\)
Quantity A |
Quantity B |
\(a+d\) |
\(b+c\) |
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.
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Which is greater a+d or b+c
[#permalink]
31 Mar 2020, 10:02
31 Mar 2020, 10:02
1
4
Bookmarks
Carcass wrote:
\(\frac{a}{b}= \frac{3}{7} = \frac{c}{d}\)
Quantity A |
Quantity B |
\(a+d\) |
\(b+c\) |
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.
Key concept: Just because a/b = 3/7, does not mean a = 3 and b = 7
For example, if a = 12 and b = 28, then a/b = 12/28 = 3/7
Likewise, if a = -30 and b = -70, then a/b = -30/-70 = 3/7
Given the wide variety of possible values, it feels like the correct answer is D
So, let's test some possible values
case i: If \(\frac{a}{b}= \frac{3}{7} = \frac{c}{d}\), then it could be the case that a = 3, b = 7, c = 12 and d = 28:
We get:
Quantity A: \(a+d=3+28=31\)
Quantity B: \(b+c=7+12=19\)
In this case, Quantity A is greater
case ii: If \(\frac{a}{b}= \frac{3}{7} = \frac{c}{d}\), then it could be the case that a = 3, b = 7, c = -30 and d = -70:
We get:
Quantity A: \(a+d=3+(-70)=-67\)
Quantity B: \(b+c=7+(-30)=-23\)
In this case, Quantity B is greater
Answer: D
RELATED VIDEO
General Discussion
Retired Moderator
Joined: 02 Jan 2020
Status:GRE Quant Tutor
Posts: 1141
Given Kudos: 9
Location: India
Concentration: General Management
Schools: XLRI Jamshedpur, India - Class of 2014
GMAT 1: 700 Q51 V31
GPA: 2.8
WE:Engineering (Computer Software)
Re: Which is greater a+d or b+c
[#permalink]
18 Jun 2021, 10:31
18 Jun 2021, 10:31
2
\(\frac{a}{b}= \frac{3}{7}\) then we can take
a = 3x and b = 7x [where x was the common integer which got cancelled when we divided a by b]
\(\frac{3}{7} = \frac{c}{d}\) then we can take
c = 3y and d = 7y [where y was the common integer which got cancelled when we divided c by d]
Quantity A = a + d = 3x + 7y
Quantity B = b + c = 7x + 3y
Now there is no way we can tell whether 3x + 7y = 7x + 3y or not, as we do not know the values of x and y
So, Answer will be D
Hope it helps!
a = 3x and b = 7x [where x was the common integer which got cancelled when we divided a by b]
\(\frac{3}{7} = \frac{c}{d}\) then we can take
c = 3y and d = 7y [where y was the common integer which got cancelled when we divided c by d]
Quantity A = a + d = 3x + 7y
Quantity B = b + c = 7x + 3y
Now there is no way we can tell whether 3x + 7y = 7x + 3y or not, as we do not know the values of x and y
So, Answer will be D
Hope it helps!
