GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 06 Dec 2019, 11:11

### 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

# A company sells peanut butter in cylindrical jars. Marketing research

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 59587
A company sells peanut butter in cylindrical jars. Marketing research  [#permalink]

### Show Tags

21 Mar 2019, 04:41
00:00

Difficulty:

55% (hard)

Question Stats:

56% (02:29) correct 44% (02:49) wrong based on 43 sessions

### HideShow timer Statistics

A company sells peanut butter in cylindrical jars. Marketing research suggests that using wider jars will increase sales. If the diameter of the jars is increased by 25% without altering the volume, by what percent must the height be decreased?

(A) 10
(B) 25
(C) 36
(D) 50
(E) 60

_________________
GMAT Club Legend
Joined: 18 Aug 2017
Posts: 5428
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: A company sells peanut butter in cylindrical jars. Marketing research  [#permalink]

### Show Tags

21 Mar 2019, 09:22
Bunuel wrote:
A company sells peanut butter in cylindrical jars. Marketing research suggests that using wider jars will increase sales. If the diameter of the jars is increased by 25% without altering the volume, by what percent must the height be decreased?

(A) 10
(B) 25
(C) 36
(D) 50
(E) 60

let intial r=2 ; d=4 & h = 1
vol= pi * 4
after increase diameter 25% ; 1.25*4 = 5 = d = r = 2.5
so vol. 6.25pi
% decrease to be done = 6.25-4/6.25 = 36%
IMO C
Target Test Prep Representative
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 8620
Location: United States (CA)
Re: A company sells peanut butter in cylindrical jars. Marketing research  [#permalink]

### Show Tags

24 Mar 2019, 18:31
1
Bunuel wrote:
A company sells peanut butter in cylindrical jars. Marketing research suggests that using wider jars will increase sales. If the diameter of the jars is increased by 25% without altering the volume, by what percent must the height be decreased?

(A) 10
(B) 25
(C) 36
(D) 50
(E) 60

We can let the initial diameter = 8, so the new diameter = 5/4 x 8 = 10. So the old radius is 4, and the new radius is 5. We can also let the old height = 10, and the new height = h.

Thus, the old volume is:

4^2 x 10 x π = 160π

The new volume is:

5^2 x h x π = 25hπ

Since the two volumes are the same, we can set 25hπ equal to 160π and solve for h:

25hπ = 160π

25h = 160

h = 6.4

Thus, the percent change between the old height and the new height is:

(6.4 - 10)/10 x 100 = (-3.6)/10 x 100 = -36 percent, i.e., a 36 percent decrease

_________________

# Scott Woodbury-Stewart

Founder and CEO

Scott@TargetTestPrep.com
122 Reviews

5-star rated online GMAT quant
self study course

See why Target Test Prep is the top rated GMAT quant course on GMAT Club. Read Our Reviews

If you find one of my posts helpful, please take a moment to click on the "Kudos" button.

Re: A company sells peanut butter in cylindrical jars. Marketing research   [#permalink] 24 Mar 2019, 18:31
Display posts from previous: Sort by