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.
Apr 25Crafting an Impactful Resume: Balancing Detail with Brevity
10:00 AM EDT
-10:30 AM EDT
Showcase your achievements through impactful storytelling! Get ready for an LIVE session on April 25, Learn how to craft compelling narratives on your resume that resonate with admission committees.
Apr 26Get a Top GRE Score with Target Test Prep
12:00 PM EDT
-01:00 PM EDT
The Target Test Prep course represents a quantum leap forward in GRE preparation, a radical reinterpretation of the way that students should study. In fact, more and more Target Test Prep students are scoring 329 and above on the GRE.
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
A marketing firm determined that, of 200 households surveyed
[#permalink]
22 Sep 2016, 12:04
22 Sep 2016, 12:04
1
6
Bookmarks
00:00
Question Stats:
60% (01:34) correct
40% (02:11) wrong based on 70 sessions
Hide Show timer Statistics
A marketing firm determined that, of 200 households surveyed, 80 used neither Brand A nor Brand B soap, 60 used only Brand A soap, and for every household that used both brands of soap, 3 used only Brand B soap. How many of the 200 households surveyed used both brands of soap?
(A) 15
(B) 20
(C) 30
(D) 40
(E) 45
(A) 15
(B) 20
(C) 30
(D) 40
(E) 45
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
A marketing firm determined that, of 200 households surveyed
[#permalink]
22 Sep 2016, 12:05
22 Sep 2016, 12:05
3
GreenlightTestPrep wrote:
A marketing firm determined that, of 200 households surveyed, 80 used neither Brand A nor Brand B soap, 60 used only Brand A soap, and for every household that used both brands of soap, 3 used only Brand B soap. How many of the 200 households surveyed used both brands of soap?
(A) 15
(B) 20
(C) 30
(D) 40
(E) 45
(A) 15
(B) 20
(C) 30
(D) 40
(E) 45
Here's a step-by-step approach using the Double Matrix method.
Here, we have a population of 200 households , and the two characteristics are:
- using or not using Brand A soap
- using or not using Brand B soap
So, we can set up our matrix as follows (where "~" represents "not"):
80 used neither Brand A nor Brand B soap
We can add this to our diagram as follows:
60 used only Brand A soap
We get...
At this point, we can see that the right-hand column adds to 140, which means 140 households do NOT use brand B soap.
Since there are 200 households altogether, we can conclude that 60 households DO use brand B soap.
For every household that used BOTH brands of soap...
Let's let x = # of households that use BOTH brands....
...3 used only Brand B soap.
So, 3x = # of households that use ONLY brand B soap
At this point, when we examine the left-hand column, we can see that x + 3x = 60
Simplify to get 4x = 60
Solve to get x = 15
How many of the 200 households surveyed used BOTH brands of soap?
Since x = # of households that use BOTH brands of soap, the correct answer here is: A
RELATED VIDEO
MORE PRACTICE
Re: A marketing firm determined that, of 200 households surveyed
[#permalink]
03 Jun 2019, 07:47
03 Jun 2019, 07:47
This math is little confusing to me -
for example, for every household that used both brands of soap, 3 used only Brand B soap. how come we find 3 households use ONLY brand B?
I request for little more elucidation , if there is any. Regards
for example, for every household that used both brands of soap, 3 used only Brand B soap. how come we find 3 households use ONLY brand B?
I request for little more elucidation , if there is any. Regards
