Last visit was: 14 Dec 2024, 06:43 It is currently 14 Dec 2024, 06:43
Close
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
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.
Close
Request Expert Reply
Confirm Cancel
User avatar
Sajjad1994
User avatar
GRE Forum Moderator
Joined: 02 Nov 2016
Last visit: 13 Dec 2024
Posts: 14,150
Own Kudos:
41,622
 []
Given Kudos: 5,905
GPA: 3.62
Products:
Posts: 14,150
Kudos: 41,622
 []
2
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
KSBGC
Joined: 31 Oct 2013
Last visit: 10 Mar 2022
Posts: 1,257
Own Kudos:
1,307
 []
Given Kudos: 635
Concentration: Accounting, Finance
GPA: 3.68
WE:Analyst (Accounting)
Posts: 1,257
Kudos: 1,307
 []
4
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
General Discussion
User avatar
Abhishek009
User avatar
Board of Directors
Joined: 11 Jun 2011
Last visit: 02 Oct 2024
Posts: 6,014
Own Kudos:
4,952
 []
Given Kudos: 463
Status:QA & VA Forum Moderator
Location: India
GPA: 3.5
WE:Business Development (Commercial Banking)
Posts: 6,014
Kudos: 4,952
 []
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
broall
User avatar
Retired Moderator
Joined: 10 Oct 2016
Last visit: 07 Apr 2021
Posts: 1,141
Own Kudos:
6,616
 []
Given Kudos: 65
Status:Long way to go!
Location: Viet Nam
Posts: 1,141
Kudos: 6,616
 []
2
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
SajjadAhmad
Which one of the following is the minimum value of the sum of two integers whose product is 36?
(A) 37
(B) 20
(C) 15
(D) 13
(E) 12

\((a-b)^2 \geq 0 \iff (a+b)^2 \geq 4ab \iff a+b \geq 2\sqrt{ab} \quad \forall a,b>0\)

Hence \(a+b \geq 2\sqrt{ab} =2\sqrt{36} =12 \iff a=b=6\)

The answer is E

Mathematically, AM-GM inequality is defined that: \(x+y \geq 2\sqrt{xy} \quad \forall x,y \geq 0\)
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 13 Dec 2024
Posts: 19,869
Own Kudos:
24,292
 []
Given Kudos: 288
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 19,869
Kudos: 24,292
 []
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
SajjadAhmad
Which one of the following is the minimum value of the sum of two integers whose product is 36?
(A) 37
(B) 20
(C) 15
(D) 13
(E) 12

Source: Nova GMAT
Difficulty Level: 550


We have the following positive integers that yield a product of 36.

1 and 36

2 and 18

3 and 12

4 and 9

6 and 6

Thus, the minimum sum is 6 + 6 = 12.

Alternate Solution:

It is a well-known fact that for a given area of a rectangle, the smallest perimeter is obtained when the shape is a square. We can use this fact, noting that xy = 36 is an area formula, where x = length and y = width. Thus, since a square has length and width equal, we see that x = y, so we can have x^2 = 36, and so x = 6. Thus, the minimum sum (half-perimeter) will be 6 + 6 = 12.

Answer: E
Moderator:
Math Expert
97874 posts